2016
- titre
- Deterministic modeling of the impact of underground structures on urban groundwater temperature
- auteur
- Guillaume Attard, Yvan Rossier, Thierry Winiarski, Laurent Eisenlohr
- article
- Science of the Total Environment, 2016, 572, pp.986 - 994. ⟨10.1016/j.scitotenv.2016.07.229⟩
- resume
- Underground structures have a major in␣uence on groundwater temperature and have a major contribution on the anthropogenic heat ␣uxes into urban aquifers. Groundwater temperature is crucial for resource management as it can provide operational sustainability indicators for groundwater quality and geothermal energy. Here, a three dimensional heat transport modeling approach was conducted to quantify the thermally affected zone (TAZ, i.e. increase in temperature of more than +0.5 °C) caused by two common underground structures: (1) an impervious structure and (2) a draining structure. These design techniques consist in (1) ballasting the un- derground structure in order to resist hydrostatic pressure, or (2) draining the groundwater under the structure in order to remove the hydrostatic pressure. The volume of the TAZ caused by these underground structures was shown to range from 14 to 20 times the volume of the underground structure. Additionally, the cumulative im- pact of underground structures was assessed under average thermal conditions at the scale of the greater Lyon area (France). The heat island effect caused by underground structures was highlighted in the business center of the city. Increase in temperature of more than +4.5 °C were locally put in evidence. The annual heat ␣ow from underground structures to the urban aquifer was computed deterministically and represents 4.5 GW·h. Considering these impacts, the TAZ of deep underground structures should be taken into account in the geother- mal potential mapping. Finally, the amount of heat energy provided should be used as an indicator of heating po- tential in these areas.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.scitotenv.2016.07.229
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- titre
- New record of fossil wood Xenoxylon from the Late Triassic in the Sichuan Basin, southern China and its paleoclimatic implications
- auteur
- Ning Tian, Yongdong Wang, Marc Philippe, Liqin Li, Xiaoping Xie, Zikun Jiang
- article
- Palaeogeography, Palaeoclimatology, Palaeoecology, 2016, 464, pp.65-75. ⟨10.1016/j.palaeo.2016.02.006⟩
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.palaeo.2016.02.006
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-

- titre
- Influence of the irrigation technique and strategies on the nitrogen cycle and budget: A review
- auteur
- Mohammad Barakat, Bruno Cheviron, Rafaël Angulo-Jaramillo
- article
- Agricultural Water Management, 2016, 178, pp.225-238. ⟨10.1016/j.agwat.2016.09.027⟩
- resume
- The objective of this review is to remedy the lack of knowledge about the expected relationship between the irrigation techniques (flood irrigation, sprinkler irrigation, surface and subsurface drip irrigation) and the nitrogen transformations (fixation, mineralization, immobilization and nitrification) or fluxes (denitrification, runoff, volatilization and lixiviation) in agricultural contexts. This study investigates thus the various controls on the nitrogen cycle and budget, either site-specific (soil C/N ratio, pH, salinity, texture and temperature) or corresponding to deliberate strategies in water and nitrogen management. The comprehensive view gained from the gathered literature elements identifies the local variations (in space and time) of soil water content profile as both the strongest control and the control most directly related to the irrigation technique and to the practitioner’s decisions. In the overall picture, flood irrigation and sprinkler irrigation are the techniques in which most transformations or fluxes may be enhanced or reduced, also with the risks associated with non-optimal practices. By contrast, subsurface drip irrigation seems the technique with the least unwanted impacts. Besides the academic aspects (bringing together scattered literature elements) an outcome of this review is thus to facilitate decision-making regarding the choice and/or use of irrigation-fertilization techniques and strategies (doses and scheduling) for given agro-pedoclimatic contexts, also for combined agricultural production, economic and site preservation objectives.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.agwat.2016.09.027
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- titre
- Individual and joint toxicity of the herbicide S-metolachlor and a metabolite, deethylatrazine on aquatic crustaceans: Difference between ecological groups
- auteur
- Chafik Maazouzi, Charlotte Coureau, Christophe Piscart, Maritxu Saplairoles, Nicole Baran, Pierre Marmonier
- article
- Chemosphere, 2016, 165, pp.118-125. ⟨10.1016/j.chemosphere.2016.09.030⟩
- resume
- We studied the individual and joint acute toxicity of S-metolachlor (SMOC) and deethylatrazine (DEA - a metabolite of atrazine) on different non-target freshwater crustaceans. We used animals from different ecological groups: two amphipods from surface running water (Gammarus pulex and Gammarus cf. orinos), an isopod from surface stagnant water (Asellus aquaticus) and an amphipod living in groundwater (Niphargus rhenorhodanensis). Organisms were exposed to different levels of SMOC and DEA, alone or in binary mixture. Temperature effect on SMOC toxicity was assessed by exposing G. pulex and N. rhenorhodanensis to SMOC at 11 degrees C and 15 degrees C. Studying mortality as the biological endpoint, N. rhenorhodanensis was more resistant than surface water species towards SMOC and DEA. Among surface water species, G. pulex was the most sensitive while Gammarus cf. orinos and A. aquaticus showed similar responses to both compounds. Temperature increase did not change SMOC toxicity but modify the shape and steepness of the dose-response curve. We used a Model Deviation Ratio (MDR) approach to evaluate the predictability of Concentration Addition (CA) and Independent Action (IA) models to mixture toxicity. Results indicated either an additive or an antagonistic or a synergistic interaction depending on the concentrations combination and the test species. Our finding conclusively show the suitability of CA and IA in predicting mixture toxicities but results should be interpreted with caution according to ecological group of exposed species in risk assessment procedures.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.chemosphere.2016.09.030
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- titre
- Le titane dans les sédiments de l'assainissement pluvial urbain : sources, concentrations, mobilités
- auteur
- Julie Bourdoiseau, Cécile Delolme
- article
- Environnement, Ingénierie & Développement, 2016, N°71 - octobre 2016, pp.35-48. ⟨10.4267/dechets-sciences-techniques.3416⟩
- resume
- Titanium is largely used in the urban environment. The purpose of this study is to characterize the titanium geochemical signature in urban stormwater sediments. Firstly, we compared the titanium, iron, silica, copper, zinc and lead content in 800 river sediments collected in Europe with the content of 19 urban sediments collected in stormwater infiltration basins in Lyon. Even if the total titanium content is not higher in urban sediment (mean of 2,7 g/kg) than in river sediments (1,5 à 4,0 g/kg), urban sediments concentrate titanium in comparison to other main minerals like silica and is correlated to heavy metals. Thus, the urban environment produce eroded particles that have a specific geochemical signature. Secondly, the study of the potentiel soluble or colloïdal mobility of titanium in urban sediment through batch experiments shows that titanium has a very low mobility in soluble or colloïdal form (less than 0,005% of the total titanium content). The organic matter present in urban sediment is supposed to play a major role on the limitation of the mobility of colloïdal titanium.
- typdoc
- Journal articles
- DOI
- DOI : 10.4267/dechets-sciences-techniques.3416
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-
- titre
- Gauging scale effects and biogeographical signals in similarity distance decay analyses: an Early Jurassic ammonite case study.
- auteur
- Axelle Zacaï, Arnaud Brayard, Jean-Louis Dommergues, Christian Meister, Gilles Escarguel, Rémi Laffont, Bruno Vrielynck, Emmanuel Fara
- article
- Palaeontology, 2016, 59 (5), pp.671-687 ⟨10.1111/pala.12250⟩
- resume
- In biogeography, the similarity distance decay (SDD) relationship refers to the decrease in compositional similarity between communities with geographical distance. Although representing one of the most widely used relationships in biogeography, a review of the literature reveals that: (1) SDD is influenced by both spatial extent and sample size; (2) the potential effect of the phylogenetic level has yet to be tested; (3) the effect of a marked biogeographical structuring upon SDD patterns is largely unknown; and (4) the SDD relationship is usually explored with modern, mainly terrestrial organisms, whereas fossil taxa are seldom used in that perspective. Using this relationship, we explore the long-distance dispersal of the Early Jurassic (early Pliensbachian, c. 190.8 Ma to 187.6 Ma) ammonites of the western Tethys and adjacent areas, in a context of marked provincialism. We show that the long-distance dispersal of these ammonites is not related to shell size and shape, but rather to the environmental characteristics of the province to which they belong. This suggests that their long-distance dispersal may have been essentially driven by passive planktonic drift during early juvenile, post-hatching stages. Furthermore, it seems that the SDD relationship is not always an appropriate method to characterize the existence of a biogeographical structuring. We conducted SDD analyses at various spatial, sampling and phylogenetic scales in order to evaluate their sensitivity to scale effects. This multi-scale approach indicates that the sampling scale may influence SDD rates in an unpredictable way and that the phylogenetic level has a major impact on SDD patterns.
- typdoc
- Journal articles
- DOI
- DOI : 10.1111/pala.12250
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-

- titre
- Accumulation and detoxication responses of the gastropod Lymnaea stagnalis to single and combined exposures to natural (cyanobacteria) and anthropogenic (the herbicide RoundUp® Flash) stressors
- auteur
- Emilie Lance, Julia L. Desprat, Bente Frost Holbech, Claudia Gerard, Myriam Bormans, Linda A. Lawton, Christine Edwards, Claudia Wiegand
- article
- Aquatic Toxicology, 2016, 177, pp.116-124. ⟨10.1016/j.aquatox.2016.05.024⟩
- resume
- Freshwater gastropods are increasingly exposed to multiple stressors in the field such as the herbi- cide glyphosate in Roundup formulations and cyanobacterial blooms either producing or not producing microcystins (MCs), potentially leading to interacting effects. Here, the responses of Lymnaea stagnalis to a 21-day exposure to non-MC or MC-producing (33 ug L−1 ) Planktothrix agardhii alone or in combination with the commercial formulation RoundUp® Flash at a concentration of 1 ug L−1 glyphosate, followed by 14 days of depuration, were studied via i) accumulation of free and bound MCs in tissues, and ii) activities of anti-oxidant (catalase CAT) and biotransformation (glutathione-S-transferase GST) enzymes. During the intoxication, the cyanobacterial exposure induced an early increase of CAT activity, independently of the MC content, probably related to the production of secondary cyanobacterial metabolites. The GST activity was induced by RoundUp® Flash alone or in combination with non MC-producing cyanobacte- ria, but was inhibited by MC-producing cyanobacteria with or without RoundUp® Flash. Moreover, MC accumulation in L. stagnalis was 3.2 times increased when snails were concomitantly exposed to MC- producing cyanobacteria with RoundUp®, suggesting interacting effects of MCs on biotransformation processes. The potent inhibition of detoxication systems by MCs and RoundUp® Flash was reversible during the depuration, during which CAT and GST activities were significantly higher in snails previ- ously exposed to MC-producing cyanobacteria with or without RoundUp® Flash than in other conditions, probably related to the oxidative stress caused by accumulated MCs remaining in tissues.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.aquatox.2016.05.024
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- titre
- Combining different assays and chemical analysis to characterize the genotoxicity of waters impacted by textile discharges
- auteur
- Francine I. Vacchi, Josiane A. S. Vendemiatti, Vanessa Brosselin, Bianca Ferreira Da Silva, Maria Valnice B. Zanoni, Michel Demeo, Sylvie Bony, Alain Devaux, Gisela A. Umbuzeiro
- article
- Environmental and Molecular Mutagenesis, 2016, 57 (7), pp.559--571. ⟨10.1002/em.22034⟩
- resume
- Waters receiving textile discharges can exhibit genotoxic and mutagenic activity, which has been related to the presence of dyes and aromatic amines as synthesis precursors or byproducts. The aim of this study was to identify dyes and aromatic amines in water samples impacted by textile discharges, and to evaluate the genotoxic responses of these samples using the Salmonella/microsome assay in strains TA98 and YG1041, and the Fpg-modified comet assay in the RTL-W1 fish cell line. The genotoxicity of river samples downstream of the discharge was greater than the upstream samples in both of the Ames tests. The Fpg-modified comet assay detected similar levels of DNA damage in the upstream and downstream samples. Mutagenicity was not detected with TA98, except for the Quilombo River samples, but when YG1041 was used as the tester strain mutagenicity was detected for all sites with a very different profile in upstream sites relative to the other sites. The mutagenic response strongly indicated that aromatic amines or dyes were contributing to the mutagenic activity downstream. The impact of textile discharges was also confirmed by chemical analysis, because the highest concentrations of azo dyes and aromatic amines were detected in the river downstream. This study shows the value of combining assays measuring complementary endpoints to better characterize the mutagenicity of environmental samples, with the advantage that this approach provides an indication of what classes of compounds are responsible for the effect. Environ. Mol. Mutagen. 57:559-571, 2016. (c) 2016 Wiley Periodicals, Inc.
- typdoc
- Journal articles
- DOI
- DOI : 10.1002/em.22034
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-

- titre
- Chronic exposure to soil salinity in terrestrial species: Does plasticity and underlying physiology differ among specialized ground-dwelling spiders?
- auteur
- David Renault, Charlène Puzin, Natacha Foucreau, Alain Bouchereau, Julien Pétillon
- article
- Journal of Insect Physiology, 2016, 90, pp.49-58. ⟨10.1016/j.jinsphys.2016.05.005⟩
- resume
- In salt marshes, the alternation of low and high tides entails rapid shifts of submersion and aerial exposure for terrestrial communities. In these intertidal environments, terrestrial species have to deal with an osmotic loss in body water content and an increase in sodium chloride concentration when salt load increases. In salt marshes, spiders represent an abundant arthropod group, whose physiological ecology in response to variations of soil salinity must be further investigated. In this study, we compared the effect of salinity on the survival and physiology of three species of Lycosidae; two salt marsh species (Arctosa fulvolineata and Pardosa purbeckensis) and one forest species (P. saltans). Spiders were individually exposed at three salinity conditions (0‰, 35‰ and 70‰) and survival, changes in body water content, hemolymph ions (Na+, Ca2+, Mg2+, K+; ICP-MS technique) and metabolites (mainly amino acids, polyols, sugars; LC and GC techniques) were assessed. The survival of the forest species P. saltans was very quickly hampered at moderate and high salinities. In this spider, variations of hemolymph ions and metabolites revealed a quick loss of physiological homeostasis and a rapid salt-induced dehydration of the specimens. Conversely, high survival durations were measured in the two salt-marsh spiders, and more particularly in A. fulvolineata. In both P. purbeckensis and A. fulvolineata, the proportion of Na+, Ca2+, Mg2+, K+ remained constant at the three experimental conditions. Accumulation of hemolymph Na+ and amino acids (mainly glutamine and proline) demonstrated stronger osmoregulatory capacities in these salt-marsh resident spiders. To conclude, even if phylogenetically close (belonging to the same, monophyletic, family), we found different physiological capacities to cope with salt load among the three tested spider species. Nevertheless, physiological responses to salinity were highly consistent with the realized ecological niches of the spiders. © 2016 Elsevier Ltd.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.jinsphys.2016.05.005
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- titre
- Experimental and modeling of the unsaturated transports of S-metolachlor and its metabolites in glaciofluvial vadose zone solids
- auteur
- Pauline Sidoli, Laurent Lassabatère, Rafaël Angulo-Jaramillo, Nicole Baran
- article
- Journal of Contaminant Hydrology, 2016, 190, pp.1 - 14. ⟨10.1016/j.jconhyd.2016.04.001⟩
- resume
- The transport of pesticides to groundwater is assumed to be impacted by flow processes and geochemical interactions occurring in the vadose zone. In this study, the transport of S-metolachlor (SMOC) and its two metabolites ESA-metolachlor (MESA) and OXA-metolachlor (MOXA) in vadose zone materials of a glaciofluvial aquifer is studied at laboratory scale. Column experiments are used to study the leaching of a conservative tracer (bromide) and SMOC, MESA and MOXA under unsaturated conditions in two lithofacies, a bimodal gravel (Gcm,b) and a sand (S-x). Tracer experiments showed water fractionation into mobile and immobile compartments more pronounced in bimodal gravel columns. In both lithofacies columns, SMOC outflow is delayed (retardation factor > 2) and mass balance reveals depletion (mass balance of 0.59 and 0.77 in bimodal gravel and sand, respectively). However, complete mass elution associated with retardation factors close to unity shows that there is no adsorption of MESA and MOXA in either lithofacies. SMOC transport is characterized by non-equilibrium sorption and sink term in both bimodal gravel and sand columns. Batch experiments carried out using agitation times consistent with column water residence times confirmed a time-dependence of SMOC sorption and high adsorption rates (> 80%) of applied concentrations. Desorption experiments confirm the irreversibility of a major part of the SMOC adsorption onto particles, corresponding to the sink term in columns. In the bimodal gravel column, SMOC adsorption occurs mainly on reactive particles in contact with mobile water because of flow regionalization whereas in the sand column, there is pesticide diffusion to the immobile water. Such results clearly show that sorption mechanisms in the vadose zone solids below the soil are both solute and contact-time-dependent and are impacted by hydrodynamic conditions. The more rapid transport of MESA and MOXA to the aquifer would be controlled mainly by water flow through the unsaturated zone whereas SMOC transport is retarded by sorption processes within the vadose zone.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.jconhyd.2016.04.001
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- titre
- Understanding clonal plant competition for space over time: a fine-scale spatial approach based on experimental communities
- auteur
- Hugo Saiz, Anne‐kristel Bittebière, Marie-Lise Benot, Vincent Jung, Cendrine Mony
- article
- Journal of Vegetation Science, 2016, 27 (4), pp.759-770. ⟨10.1111/jvs.12392⟩
- resume
- Aims: Competitive interactions are a determinant driver of plant community structure in temperate grasslands. In such dense vegetation cover, competition mostly occurs over free space, which conditions niche availability. Clonal growth determines how plants exploit horizontal space, by (1) exploring and colonizing free patches (guerilla form) or (2) resisting competitors through space consolidation (phalanx form), with possible intermediate strategies. Few studies have explored the dynamics of co-existing plants belonging to different clonal strategies. Models predict that guerilla forms may be advantageous during the early stages of succession, whereas phalanx forms are expected to be better com- petitors over time. We investigated whether these predictions are true under experimental conditions and explored possible mechanisms that promote clonal plant co-existence.Location: Experimental garden of the University of Rennes 1, France.Methods: We set up a large-scale mesocosm, in which we manipulated differ- ent mixtures of three clonal growth forms (guerilla, intermediate and phalanx) over 5 yr (2009–2014), which impeded all types of reproduction other than clonal spread of the initial planted individuals. We analysed the spatio-temporal dynamics of the communities using linear mixed models to compare the change in relative cover and spatial association (differentiating between associations with similar and different species) for each clonal form.Results: Guerilla forms dominated the early community, but decreased in dom- inance at later stages, at which point intermediate forms benefitted. Further- more, guerilla forms were more likely to co-occur with other guerrillas, with this pattern remaining consistent over time. In contrast, and contrary to our expectations, phalanx forms had the lowest cover throughout the experiment, and exhibited clear segregation from intermediate or other phalanx species. Intermediate growth forms between guerilla and phalanx were the most vari- able over time, displaying both consolidative and explorative patterns depending on the clonal forms of the other species which they coexisted with, suggesting plastic variation in their traits.Conclusions: Our results highlight the key role of clonal forms in driving com- petitive interactions and, hence, determining the spatio-temporal dynamics of grassland communities.
- typdoc
- Journal articles
- DOI
- DOI : 10.1111/jvs.12392
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- titre
- Pharmaceutical compounds removal in wastewater plants by biological treatments and tertiary ozonation
- auteur
- Adriana Gonzalez-Ospina, Bruno Domenjoud, Emmanuelle Vulliet, Agneta Kiss, Alexandre Bergé, Sylvie Bony, Alain Devaux, Adriana Wigh, Selim Aït-Aïssa, S Baig
- article
- TSM. Techniques Sciences Méthodes – Génie urbain, génie rural, 2016, 6, pp.45-58. ⟨10.1051/tsm/201606045⟩
- resume
- The choice to operate the CAS and MBBR systems with full nitrification, results in the same level of performance on pharmaceutical compounds removal for both biological systems (despite the differences on process conditions : sludge concentration, hydraulic contact time…). The biological treatment of 10 pharmaceuticals with CAS or MBBR reactor succeeded in 24% of removal of the 7 refractory compounds measured (carbamazepine, sulfamethoxazole, propranolol, atenolol, diclofenac, econazole, salicylic acid), and an average of 45% including also paracetamol, ketoprofen and ibuprofen with an important variability on performances (> 20%). The combined system CAS biolog ical treatment plus tertiary ozonation at low ozone dosage (0.45 gO3/gDOC) improves the average removal up to 92% with only one compound -econaz ole- moderately eliminated (70%). It has been observed that increasing the ozone from the low to the intermediate dosage of 1.30 gO3/gDOC leads to an average removal improvement of around 6% whereas a more important TOD (2.30 gO3/gDOC) did not led to a better performance. Contrary to the lack of toxicity observed with normalized ecotoxicity tests, endpoints measured on zebrafish embryos (FET bioassay) such as mortality, developmental abnormalities and genotoxicity demonstrated a residual toxicity (null/weak) both, in wastewater after a biological treatment followed or not by a tertiary ozonation treatment. However, the tertiary ozonation resulted in an improvement of the residual endocrine disrupting potential measured in the biologically-treated effluents. This study shows that normalized bioassays are not sensitive enough for the ecotoxicological evaluation of wastewaters and that there is a great need for the development of suitable sensitive bioassays in order to characterize properly the possible residual toxicity of differently treated effluents. The knowledge of the sample chemical fingerprints, by a comprehensive non-target approach based on the comparison of biochemical signatures, is a promising growing strategy to identify and prioritize the emerging contaminants and to contribute to the study of the treatment performance.
- typdoc
- Journal articles
- DOI
- DOI : 10.1051/tsm/201606045
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- titre
- A diagenetic control on the Early Triassic Smithian-Spathian carbon isotopic excursions recorded in the marine settings of the Thaynes Group (Utah, USA).
- auteur
- Christophe Thomazo, Emmanuelle Vennin, Arnaud Brayard, Ivan Bour, Olivier Mathieu, S. Elmeknassi, Nicolas Olivier, Gilles Escarguel, K.G. Bylund, J. Jenks, D.A. Stephen, Emmanuel Fara
- article
- Geobiology, 2016, 14 (3), pp.220-236. ⟨10.1111/gbi.12174⟩
- resume
- n the aftermath of the end-Permian mass extinction, Early Triassic sediments record some of the largest Phanerozoic carbon isotopic excursions. Among them, a global Smithian-negative carbonate carbon isotope excursion has been identified, followed by an abrupt increase across the Smithian–Spathian boundary (SSB; ~250.8 Myr ago). This chemostratigraphic evolution is associated with palaeontological evidence that indicate a major collapse of terrestrial and marine ecosystems during the Late Smithian. It is commonly assumed that Smithian and Spathian isotopic variations are intimately linked to major perturbations in the exogenic carbon reservoir. We present paired carbon isotopes measurements from the Thaynes Group (Utah, USA) to evaluate the extent to which the Early Triassic isotopic perturbations reflect changes in the exogenic carbon cycle. The δ13Ccarb variations obtained here reproduce the known Smithian δ13Ccarb-negative excursion. However, the δ13C signal of the bulk organic matter is invariant across the SSB and variations in the δ34S signal of sedimentary sulphides are interpreted here to reflect the intensity of sediment remobilization. We argue that Middle to Late Smithian δ13Ccarb signal in the shallow marine environments of the Thaynes Group does not reflect secular evolution of the exogenic carbon cycle but rather physicochemical conditions at the sediment–water interface leading to authigenic carbonate formation during early diagenetic processes.
- typdoc
- Journal articles
- DOI
- DOI : 10.1111/gbi.12174
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- titre
- Accelerated body size evolution during cold climatic periods in the Cenozoic
- auteur
- Julien Clavel, Hélène Morlon
- article
- Proceedings of the National Academy of Sciences of the United States of America, 2016, 114, pp.4183 - 4188. ⟨10.1073/pnas.1606868114⟩
- typdoc
- Journal articles
- DOI
- DOI : 10.1073/pnas.1606868114
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- titre
- Xanthan Exopolysaccharide: Cu(2+) Complexes Affected from the pH-Dependent Conformational State; Implications for Environmentally Relevant Biopolymers.
- auteur
- Benjamin Causse, Lorenzo Spadini, Géraldine Sarret, Adeline Faure, Christophe Travelet, Dominique Madern, Cécile Delolme
- article
- Environmental Science and Technology, 2016, 50 (7), pp.3477-85. ⟨10.1021/acs.est.5b03141⟩
- resume
- The conformational impact of environmental biopolymers on metal sorption was studied through Cu sorption on xanthan. The apparent Cu(2+) complexation constant (logK; Cu(2+) + L(-) ↔ CuL(+)) decreased from 2.9 ± 0.1 at pH 3.5 to 2.5 ± 0.1 at pH 5.5 (ionic strength I = 0.1). This behavior is in apparent contradiction with basic thermodynamics, as usually the higher the pH the more cations bind. Our combined titration, circular dichroism and dynamic light scattering study indicated that the change observed in Cu bond strength relates to a conformational change of the structure of xanthan, which generates more chelating sites at pH 3.5 than at pH 5.5. This hypothesis was validated by the fact that the Cu sorption constants on xanthan were always higher than those measured on a mixture of pyruvic and glucuronic acids (logK = 2.2), which are the two constitutive ligands present in the xanthan monomer. This study shows the role of the structural conformation of natural biopolymers in metal bond strength. This finding may help to better predict the fate of Cu and other metals in acidic environmental settings such as aquatic media affected by acid mine drainage, as well as peats and acidic soils, and to better define optimal conditions for bioremediation processes.
- typdoc
- Journal articles
- DOI
- DOI : 10.1021/acs.est.5b03141
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- titre
- Effects of rising temperature on a functional process: consumption and digestion of leaf litter by a freshwater shredder
- auteur
- Natacha Foucreau, Christophe Piscart, Sara Puijalon, Frédéric Hervant
- article
- Fundamental and Applied Limnology, 2016, 187 (4), pp.295-306. ⟨10.1127/fal/2016/0841⟩
- resume
- Climate change will likely affect riparian litter decomposition in freshwater streams in future decades by modifications in both microorganism and invertebrate activities. On the one hand, the expected increase in C:N ratio will decrease the palatability of leaf litter, and consequently slow down decomposition rates of leaves. On the other hand, rising temperatures may stimulate litter decomposition. We conducted a feeding study that associated the key shredder species Gammarus pulex (Crustacea, Amphipoda) with common riparian leaf litter (from the tree Alnus glutinosa) from European freshwater streams. We assessed the effects of temperature on i) changes in leaf palatability during conditioning (microbial colonisation), ii) leaf consumption rates, and iii) leaf digestion by shredders. Moreover, we compared the responses to rising temperatures between two populations of G. pulex, living in contrasting thermal environments (humid continental climate vs. temperate Mediterranean climate). We found that the decreased mechanical resistance of leaf tissue, which was induced by the conditioning, was stimulated by an increase in temperature. However, we found no increase in fungal biomass even at the highest temperatures (21 and 24 degrees C). The leaf consumption rate by amphipods increased slightly but not linearly with rising temperatures. Moreover, digestive enzyme activities in amphipod guts were clearly favoured by an increase in water temperature. Catalytic activities of digestive enzymes were generally higher for amphipods living under continental climate conditions. Our study supported the idea that the effect of rising temperatures on the leaf litter decomposition would not be unidirectional. Higher temperatures would lead to contrasting impacts on both physiology and ecology of organisms involved in this functional process.
- typdoc
- Journal articles
- DOI
- DOI : 10.1127/fal/2016/0841
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- titre
- Biomass offsets little or none of permafrost carbon release from soils, streams, and wild␣re: an expert assessment
- auteur
- Benjamin W. Abbott, Jeremy Jones, Edward Schuur, F. Stuart Chapin, William Bowden, M. Syndonia Bret-Harte, Howard Epstein, Michael Flannigan, Tamara K. Harms, Teresa Hollingsworth, Michelle Mack, A. David Mcguire, Susan M. Natali, Adrian Rocha, Suzanne E. Tank, Merritt R. Turetsky, Jorien E. Vonk, Kimberly P. Wickland, George R. Aiken, Heather Alexander, Rainer M.W. Amon, Brian W. Benscoter, Yves Bergeron, Kevin Bishop, Olivier Blarquez, Ben Bond-Lamberty, Amy L. Breen, Ishi Buffam, Yihua Cai, Christopher Carcaillet, Sean K. Carey, Jing M. Chen, Han Y.H. Chen, Torben R. Christensen, Lee W. Cooper, J. Hans C. Cornelissen, William J. de Groot, Thomas H. Deluca, Ellen Dorrepaal, Ned Fetcher, Jacques C. Finlay, Bruce C. Forbes, Nancy H.F. French, Sylvie Gauthier, Martin P. Girardin, Scott Goetz, Johann G. Goldammer, Laura Gough, Paul Grogan, Laodong Guo, Philip E. Higuera, Larry Hinzman, Feng Sheng Hu, Gustaf Hugelius, Elchin Jafarov, Randi Jandt, Jill F Johnstone, Jan Karlsson, Eric S. Kasischke, Gerhard Kattner, Ryan Kelly, Frida Keuper, George W. Kling, Pirkko Kortelainen, Jari Kouki, Peter Kuhry, Hjalmar Laudon, Isabelle Laurion, Robie Macdonald, Paul J. Mann, Pertti J. Martikainen, James W. Mc Clelland, Ulf Molau, Steven F. Oberbauer, David Olefeldt, David Paré, Marc-André Parisien, Serge Payette, Changhui Peng, Oleg S. Pokrovsky, Edward B. Rastetter, Peter A. Raymond, Martha Raynolds, Guillermo Rein, James F. Reynolds, Martin Robard, Bredan M. Rogers, Christina Schädel, Kevin Schaefer, Inger K. Kappel Schmidt, Anatoly Shvidenko, Jasper Sky, Robert G.M. Spencer, Gregory Starr, Robert G. Striegl, Roman Teisserenc, Lars J Tranvik, Tarmo Virtanen, Jeffrey M. Welker, Sergei Zimov
- article
- Environmental Research Letters, 2016, 11 (3), pp.1-13. ⟨10.1088/1748-9326/11/3/034014⟩
- resume
- As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost-region experts of the response of biomass, wild␣re, and hydrologic carbon ␣ux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identi␣ed water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty in predicting future system response. In combination with previous ␣ndings, results suggest the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario but that 65%–85% of permafrost carbon release can still be avoided if human emissions are actively reduced.
- typdoc
- Journal articles
- DOI
- DOI : 10.1088/1748-9326/11/3/034014
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- titre
- Storm water retention and actual evapotranspiration performances of experimental greeen roofs in French oceanic climate
- auteur
- Deniz Yilmaz, Maeva Sabre, Laurent Lassabatère, Murat Dal, Fabrice Rodriguez
- article
- European Journal of Environmental and Civil Engineering, 2016, 20 (3), pp.344-362. ⟨10.1080/19648189.2015.1036128⟩
- resume
- Green roofs are promising urban management tools from the standpoint of both rainwater management and microclimatology. They are considered as a storm water mitigation technique and may also favour evapotranspiration fluxes, which can be beneficial for urban comfort during summer periods. In France, however, water retention performance of green roofs remains unknown, and published values are often unsuitable. Six experimental roofs, including two thicknesses of growing media, three types of vegetation cover and bare surfaces, were monitored for two years in Nantes and compared to an experimental gravel flat roof. The thickest media combined with the most densely vegetated cover yields the best results in terms of storm water mitigation and actual evapotranspiration. In winter, the rainwater retention performance is clearly dependent on the type of experimental roof vegetation. This kind of experimental set-up is well suited to assisting urban planners design tools for storm water mitigation in buildings.
- typdoc
- Journal articles
- DOI
- DOI : 10.1080/19648189.2015.1036128
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- titre
- Dynamics of toxicity within different compartments of a peri-urban river subject to combined sewer overflow discharges
- auteur
- Céline Becouze-Lareure, L. Thiebaud, C Bazin, Philippe Namour, Pascal Breil, Yves Perrodin
- article
- Science of the Total Environment, 2016, 539, pp.503-514. ⟨10.1016/j.scitotenv.2015.08.128⟩
- resume
- Combined Sewer Overflows (CSO) in small pen-urban streams and rivers are potentially toxic for their biocenosis. Improving the management of CSO discharges requires better knowledge of their dynamics and toxicity. In view to characterizing this toxicity, we sampled the different compartments (benthic and hyporheic zone) of a pen-urban stream located near the city of Lyon in France. The samples were taken at different distances from a CSO and at three period characteristic of different hydrological conditions. Their toxic effects were assessed by bioassays on the dissolved fraction (D. magna, V. fished and B. calyciflorus bioassays) and on the particle fraction (V. fished and H. incongruens bioassays). The results highlighted significant toxicity of the particulate fraction for the benthic and hyporheic samples, in particular downstream of the CSO, but with high spatio-temporal variability. This variability can first be attributed to the variability of CSO discharge sampling as a function of season and rainfall, and the dynamics of polluted particles (trapping of transported particles in infiltration zones, mobilization during floods). These parameters play a fundamental role in the distribution of pollutants according to the geomorphology of stream facies. Regarding dissolved pollutants, the chemical exchanges taking place at the "water-sediment" interface trigger the transfer of pollutants from one phase to another, after which the dispersion of these pollutants is governed by hydraulic flows. Finally, critical zones and periods are identified for the pen-urban river toxicity studied: benthic sediments under mean flow downstream: hyporheic sediments after a storm event downstream, close to the CSO. Recommendations are made on the basis of the knowledge obtained to optimize the management of these discharges.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.scitotenv.2015.08.128
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- titre
- Disentangling the effects of land use and geo-climatic factors on diversity in European freshwater ecosystems
- auteur
- Christian K. Feld, Sebastian Birk, David Eme, Michael Gerisch, Daniel Hering, Martin Kernan, Kairi Maileht, Ute Mischke, Ingmar Ott, Florian Pletterbauer, Sandra Poikane, Jorge Salgado, Carl Sayer, Jeroen van Wichelen, Florian Malard
- article
- Ecological Indicators, 2016, 60, pp.71 - 83. ⟨10.1016/j.ecolind.2015.06.024⟩
- resume
- Land use effects are considered among the main stressors on freshwater biodiversity, with up to 80% of land in Europe under intensive use. Here, we address the impact of arable and urban landscapes on taxon richness, Shannon–Wiener diversity, taxon rareness and taxonomic distinctness of eleven organ- ism groups encompassing vertebrates, invertebrates and plants, occurring in five freshwater ecosystem types across Europe: rivers, floodplains, lakes, ponds and groundwater. In addition, nine geo-climatic descriptors (e.g. latitude, longitude, precipitation) were used to disentangle land use effects from those of natural drivers of biodiversity. Using a variance partitioning scheme based on boosted regression trees and generalised linear regression modelling, we sought: (i) to partition the unique, shared and unex- plained variation in the metrics explained by both groups of descriptor variables, (ii) to quantify the contribution of each descriptor variable to biodiversity variation in the most parsimonious regression model and (iii) to identify interactions of land use and natural descriptors. The variation in biodiver- sity uniquely described by land use was consistently low across both ecosystem types and organism groups. In contrast, geo-climatic descriptors uniquely, and jointly with land use, explained significantly more variance in all 39 biodiversity metrics tested. Regression models revealed significant interactions between geo-climatic descriptors and land use for a third of the models, with interactions accounting for up to 17% of the model’s deviance. However, no consistent patterns were observed related to the type of biodiversity metric and organism group considered. Subdividing data according to the strongest geo-climatic gradient in each dataset aimed to reduce the strength of natural descriptors relative to land use. Although data sub-setting can highlight land use effects on freshwater biodiversity, sub-setting our data often failed to produce stronger land use effects. There was no increase in spatial congruence in the subsets, suggesting that the observed land use effects were not dependent on the spatial extent of the subsets. Our results confirm significant joint effects of, and interactions between, land use and natural environmental descriptors on freshwater biodiversity, across ecosystem types and organism groups. This has implications for biodiversity monitoring. First, the combined analysis of anthropogenic and natural descriptors is a prerequisite for the analysis of human threats to biodiversity. Second, geo-climatically, but not necessarily geographically more homogeneous datasets can help unmask the role of anthropogenic descriptors. And third, whole community-based biodiversity metrics (including taxon richness) are not ideal indicators of anthropogenic effects on biodiversity at broad scales.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.ecolind.2015.06.024
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- titre
- A new family Lepidocharontidae with description of Lepidocharon gen. n., from the Great Barrier Reef, Australia, and redefinition of the Microparasellidae (Isopoda, Asellota)
- auteur
- Diana M.P. Galassi, Niel Bruce, Barbara Fiasca, Marie-José Dole-Olivier
- article
- Zookeys, 2016, 594, pp.11-50. ⟨10.3897/zookeys.594.7539⟩
- resume
- Lepidocharontidae Galassi & Bruce, fam. n. is erected, containing Lepidocharon Galassi & Bruce, gen. n. and two genera transferred from the family Microparasellidae Karaman, 1934: Microcharon Karaman, 1934 and Janinella Albuquerque, Boulanouar & Coineau, 2014. The genus Angeliera Chappuis & Delamare Deboutteville, 1952 is placed as genus incertae sedis in this family. The Lepidocharontidae is characterised by having rectangular or trapezoidal somites in dorsal view, a single free pleonite, a tendency to reduction of the coxal plates, and the unique uropodal morphology of a large and long uropodal protopod on which the slender uropodal exopod articulates separately and anteriorly to the endopod. Lepidocharon Galassi & Bruce, gen. n. has a 6-segmented antennula, a well-developed antennal scale (rudimentary exopod), long and slender pereiopods 1–7 directed outwards, coxal plates rudimentary, incorporated to the lateral side of the sternites, not discernible in dorsal view, the single pleonite narrower than pereionite 7, scale-like elements bordering the proximal part of male pleopod 1 on posterior side, and stylet-guiding grooves of male pleopod 1 which run parallel to the outer lateral margins of the same pleopod. Lepidocharon priapus Galassi & Bruce, sp. n., type species for the genus, and Lepidocharon lizardensis Galassi & Bruce, sp. n. are described from Lizard Island, northern Great Barrier Reef. The most similar genus is Microcharon, both genera sharing the same general organization of the male pleopods 1 and 2, topology and architecture of the stylet-guiding groove of male pleopod 1, morphology of female operculum, presence of 2 robust claws of different lengths on pereiopodal dactylus 1–7, not sexually dimorphic. Lepidocharon gen. n. differs from Microcharon in the shape of the pereionites, very reduced coxal plates, the presence of imbricate scale-like elements bordering the proximal postero-lateral margins of the male pleopod 1, and the topology of the pereiopods, which are ventro-laterally inserted and directed outwards in Lepidocharon gen. n. and dorso- laterally inserted and directed ventrally in Microcharon. Lepidocharon shares with the genus Janinella the morphology of the tergites and the reduced lacinia mobilis of the left mandible, but differs significantly from Janinella in having a well-developed antennal scale, very reduced coxal plates also in females bearing oostegites, the general morphology and spatial arrangement of the stylet-guiding groove of male pleopod 1 and the possession of a 6-segmented antennula. The family Microparasellidae is redefined as monotypic, the only genus being Microparasellus Karaman, 1933.
- typdoc
- Journal articles
- DOI
- DOI : 10.3897/zookeys.594.7539
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- titre
- Gut fermentation seems to promote decompression sickness in humans
- auteur
- Sébastien de Maistre, Nicolas Vallée, Emmanuel Gempp, Pierre Louge, Claude Duchamp, Jean-Eric Blatteau
- article
- Journal of Applied Physiology, 2016, 121, pp.973-979. ⟨10.1152/japplphysiol.00503.2016⟩
- resume
- Massive bubble formation after diving can lead to decompression sickness (DCS) that can result in neurological disorders. In experimental dives using hydrogen as the diluent gas, decreasing the body's H2 burden by inoculating hydrogen-metabolizing microbes into the gut reduces the risk of DCS. In contrast, we have shown that gut bacterial fermentation in rats on a standard diet promotes DCS through endogenous hydrogen production. Therefore, we set out to test these experimental results in humans. Thirty-nine divers admitted into our hyperbaric center with neurological DCS (Affected Divers) were compared with 39 healthy divers (Unaffected Divers). Their last meal time and composition were recorded. Gut fermentation rate was estimated by measuring breath hydrogen 1-4 h after the dive. Breath hydrogen concentrations were significantly higher in Affected Divers (15 ppm [6-23] vs. 7 ppm [3-12]; P = 0.0078). With the use of a threshold value of 16.5 ppm, specificity was 87% [95% confidence interval (CI) 73-95] for association with neurological DCS onset. We observed a strong association between hydrogen values above this threshold and an accident occurrence (odds ratio = 5.3, 95% CI 1.8-15.7, P = 0.0025). However, high fermentation potential foodstuffs consumption was not different between Affected and Unaffected Divers. Gut fermentation rate at dive time seemed to be higher in Affected Divers. Hydrogen generated by fermentation diffuses throughout the body and could increase DCS risk. Prevention could be helped by excluding divers who are showing a high fermentation rate, by eliminating gas produced in gut, or even by modifying intestinal microbiota to reduce fermentation rate during a dive.
- typdoc
- Journal articles
- DOI
- DOI : 10.1152/japplphysiol.00503.2016
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- titre
- Genome Content and Phylogenomics Reveal both Ancestral and Lateral Evolutionary Pathways in Plant-Pathogenic Streptomyces Species
- auteur
- José Huguet-Tapia, Tristan Lefébure, Jonathan H Badger, Dongli Guan, Gregg S. Pettis, Michael J Stanhope, Rosemary Loria
- article
- Applied and Environmental Microbiology, 2016, 82 (7), pp.2146-2153. ⟨10.1128/AEM.03504-15⟩
- resume
- Streptomyces spp. are highly differentiated actinomycetes with large, linear chromosomes that encode an arsenal of biologically active molecules and catabolic enzymes. Members of this genus are well equipped for life in nutrient-limited environments and are common soil saprophytes. Out of the hundreds of species in the genus Streptomyces, a small group has evolved the ability to infect plants. The recent availability of Streptomyces genome sequences, including four genomes of pathogenic species, provided an opportunity to characterize the gene content specific to these pathogens and to study phylogenetic relationships among them. Genome sequencing, comparative genomics, and phylogenetic analysis enabled us to discriminate pathogenic from saprophytic Streptomyces strains; moreover, we calculated that the pathogen-specific genome contains 4,662 orthologs. Phylogenetic recon- struction suggested that Streptomyces scabies and S. ipomoeae share an ancestor but that their biosynthetic clusters encoding the required virulence factor thaxtomin have diverged. In contrast, S. turgidiscabies and S. acidiscabies, two relatively unrelated pathogens, possess highly similar thaxtomin biosynthesis clusters, which suggests that the acquisition of these genes was through lateral gene transfer.
- typdoc
- Journal articles
- DOI
- DOI : 10.1128/AEM.03504-15
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- titre
- Urban pollution of sediments: Impact on the physiology and burrowing activity of tubificid worms and consequences on biogeochemical processes
- auteur
- Mathilde Pigneret, Florian Mermillod-Blondin, Laurence Volatier, Caroline Romestaing, Eric Maire, Jérôme Adrien, Ludovic Guillard, Damien Roussel, Frédéric Hervant
- article
- Science of the Total Environment, 2016, 568 ( 196–207), ⟨10.1016/j.scitotenv.2016.05.174⟩
- resume
- In urban areas, infiltration basins are designed to manage stormwater runoff from impervious surfaces and allow the settling of associated pollutants. The sedimentary layer deposited at the surface of these structures is highly organic and multicontaminated (mainly heavy metals and hydrocarbons). Only few aquatic species are able to maintain permanent populations in such an extreme environment, including the oligochaete Limnodrilus hoffmeisteri. Nevertheless, the impact of urban pollutants on these organisms and the resulting influence on infiltration basin functioning remain poorly studied. Thus, the aim of this study was to determine how polluted sediments could impact the survival, the physiology and the bioturbation activity of L. hoffmeisteri and thereby modify biogeochemical processes occurring at the water-sediment interface. To this end, we conducted laboratory incubations of worms, in polluted sediments from infiltration basins or slightly polluted sediments from a stream. Analyses were performed to evaluate physiological state and burrowing activity (X-ray micro-tomogra- phy) of worms and their influences on biogeochemical processes (nutrient fluxes, CO2 and CH4 degassing rates) during 30-day long experiments. Our results showed that worms exhibited physiological responses to cope with high pollution levels, including a strong ability to withstand the oxidative stress linked to contamination with heavy metals. We also showed that the presence of urban pollutants significantly increased the burrowing activity of L. hoffmeisteri, demonstrating the sensitivity and the relevance of such a behavioural response as biomarker of sediment toxicity. In addition, we showed that X-ray micro-tomography was an adequate technique for accurate and non-invasive three-di- mensional investigations of biogenic structures formed by bioturbators. The presence of worms induced stimulations of nutrient fluxes and organic matter recycling (between +100% and 200% of CO2 degassing rate). Nevertheless, these stimulations were comparable within the three sediments, suggesting a low influence of urban contaminants on bioturbation-driven biogeochemical processes under our experimental conditions.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.scitotenv.2016.05.174
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- titre
- Methods for evaluating the pollution impact of urban wet weather discharges on biocenosis: A review
- auteur
- Antoine Gosset, Yannis Ferro, Claude Durrieu
- article
- Water Research, 2016, 89, pp.330-354. ⟨10.1016/j.watres.2015.11.020⟩
- resume
- Rainwater becomes loaded with a large number of pollutants when in contact with the atmosphere and urban surfaces. These pollutants (such as metals, pesticides, PAHs, PCBs) reduce the quality of water bodies. As it is now acknowledged that physico-chemical analyses alone are insufficient for identifying an ecological impact, these analyses are frequently completed or replaced by impact studies communities living in freshwater ecosystems (requiring biological indices), ecotoxicological studies, etc. Thus, different monitoring strategies have been developed over recent decades aimed at evaluating the impact of the pollution brought by urban wet weather discharges on the biocenosis of receiving aquatic ecosystems. The purpose of this review is to establish a synthetic and critical view of these different methods used, to define their advantages and disadvantages, and to provide recommendations for futures researches. Although studies on aquatic communities are used efficiently, notably on benthic macroinvertebrates, they are difficult to interpret. In addition, despite the fact that certain bioassays lack representativeness, the literature at present appears meagre regarding ecotoxicological studies conducted in situ. However, new tools for studying urban wet weather discharges have emerged, namely biosensors. The advantages of biosensors are that they allow monitoring the impact of discharges in situ and continuously. However, only one study on this subject has been identified so far, making it necessary to perform further research in this direction.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.watres.2015.11.020
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-

- titre
- The Pliensbachian-Toarcian paleoclimate transition: New insights from organic geochemistry and C, H, N isotopes in a continental section from Central Asia
- auteur
- Romain Tramoy, Johann Schnyder, T.T. Nguyen Tu, J. Yans, Jérémy Jacob, M. Sebilo, S. Derenne, M. Philippe, A. Huguet, D. Pons, François Baudin
- article
- Palaeogeography, Palaeoclimatology, Palaeoecology, 2016, 461, pp.310 - 327. ⟨10.1016/j.palaeo.2016.08.020⟩
- resume
- The Taskomirsay section (South Kazakhstan) is a unique Pliensbachian-Toarcian sequence of lignites, clayey layers and silty-sandstones deposited in a fluvial/lacustrine environment with nearby swampy areas. This period, characterized by a drastic climate change, has been particularly studied in Western Tethyan marine environments, whereas very few studies focused on continental settings. Paleoflora analyses, associated with a multi-isotope approach, based on well-preserved Type-III bulk organic nitrogen isotopes (à15Norg) and hydrogen isotopic composition (à2H) of n-alkanes, were developed to document paleoclimatic changes in the area. Sporomorph associations and fossil woods revealed a globally warm- to cool-temperate climate – characterized by Xenoxylon, a conifer morphogenus biogeographically related to cool/humid settings – apart from slightly less humid and warmer conditions in the early Toarcian. Warmer conditions are supported by reconstructed Mean Annual Air Temperatures (MAATs), based on the first branched glycerol dialkyl glycerol tetraethers (brGDGTs) ever recorded in the Early Jurassic. Nevertheless, no drastic changes were recorded in the à15Norg values; its signal being attributed to tenuous equilibrium between water- and nutrient-availability via intense N-recycling. Based on n-alkane distributions, sources of organic matter were separated in two pools: (i) a purely terrestrial (n-C27) and (ii) an “aquatic” pool (n-C23) constituted of vegetation that thrived under almost permanent water supply. The n-alkane à 2H values (␣248 to ␣151‰) as well as their amounts and average chain lengths (ACL) are in agreement with cool-temperate conditions in the Pliensbachian and less humid/warmer conditions in the early Toarcian. The isotopic difference between à2H values of n-C27 and n-C23 (␣2Hter-aq) suggests enhanced seasonality during the Pliensbachian-Toarcian transition and low seasonality in the early Toarcian, in agreement with temperate climate-regime. Finally, contrasted response to paleoclimate changes between markers suggests different spatial integration of those proxies. The role of sea-level variations for à2H values might also resolve this contrasted response.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.palaeo.2016.08.020
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- titre
- Paleoecology, biogeography, and evolution of reef ecosystems in the Panthalassa Ocean during the Late Triassic: Insights from reef limestone of the Sambosan Accretionary Complex, Shikoku, Japan
- auteur
- Camille Peybernes, Jérôme Chablais, Tetsuji Onoue, Gilles Escarguel, Rossana Martini
- article
- Palaeogeography, Palaeoclimatology, Palaeoecology, 2016, 457, pp.31-51. ⟨10.1016/j.palaeo.2016.05.032⟩
- resume
- Upper Triassic reefs from the Panthalassa Ocean have been understudied in comparison to their Tethyan counter- parts and are therefore pivotal to understanding the global reef evolution during the Late Triassic. To ␣ll this gap, Upper Triassic reef limestone from ten localities of the Sambosan Accretionary Complex at Shikoku Island (Japan) has been investigated. Biotic assemblages, quantitative microfacies analysis, and integrated biostratigraphy allow us to characterize two types of reefs, those attributed to the Ladinian?–Early Carnian and those attributed to the Late Carnian–Rhaetian? At the regional scale, our data re␣ne the biostratigraphic framework of the Upper Triassic Sambosan limestone. At the global scale, multivariate analyses support a strong paleobiogeographic af␣nity of the Western Panthalassa reef biota with those of the South Tethys Ocean during the Ladinian–Carnian and Norian–Rhaetian. Additionally, they indicate connections with East Panthalassa reefs during the Norian–Rhaetian.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.palaeo.2016.05.032
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- titre
- Impact of cadmium on the ecdysteroids production in Gammarus fossarum
- auteur
- Sondes Abidi, Khedidja Tair Abbaci, Olivier Geffard, Moncef Boumaiza, Adeline Dumet, Jeanne Garric, Nathalie Mondy
- article
- Ecotoxicology, 2016, 25 (5), pp.880-887. ⟨10.1007/s10646-016-1645-7⟩
- resume
- Gammarus fossarum is an important test organism which is currently used as a bio-indicator as well as in ecotoxicological tests. Nevertheless, data on ecdys- teroids in endocrine toxicity test are not yet available for these species, despite its crucial role in molting and reproduction. In the present paper, ecdysteroids concen- trations were studied during the molt cycle (in females) and embryonic development in G. fossarum (Crustacea, Amphipoda) in order to propose an ecdysteroids toxicity test. Ecdysteroids levels in G. fossarum showed a single peak during premolt at stage Dl-D2. In embryos, ecdys- teroids levels progressively increased over stages 3 and 4, with peak levels at stage 4. A Cadmium toxicity test was proposed to examine if the molting and embryogenesis disturbances previously observed after cadmium exposure (Geffard et al. 2010) could be attributed to changes in ecdysteroids titers. Exposure to the different cadmium concentrations (3; 9; 300; 900 lg/l) increased ecdysteroids secretion by Y-organs in vitro, but it had no significant effect on exposed embryos (in vivo). Based on previous findings, we are led to conclude that the molting impairments in cadmium-exposed females of G. fossarum is connected to the changes in ecdysteroids concentrations.
- typdoc
- Journal articles
- DOI
- DOI : 10.1007/s10646-016-1645-7
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- titre
- Beneficial effects of group size on oxidative balance in a wild cooperative breeder
- auteur
- Sophie Lardy, Benjamin Rey, Karine Salin, Yann Voituron, Aurélie Cohas
- article
- Behavioral Ecology, 2016, 27 (6), pp.1820-1825. ⟨10.1093/beheco/arw114⟩
- resume
- Social factors have important effects on individuals’ fitness, yet the proximate mechanisms remain virtually unknown. Oxidative stress, which results from the imbalance between the systemic effect of reactive oxygen species on molecules and an organism’s capacity to restore oxidative balance, is one potential mechanism mediating such effects. Although individuals’ oxidative balance seems to be affected by their social status, the effects of social environment, and particularly group size and composition, on oxidative balance have seldom been determined in wild populations. Here, we investigated the influence of group size and composition on the oxida- tive balance of wild dominant Alpine marmots (Marmota marmota). We simultaneously measured an index of circulating oxidative damage to lipids (thiobarbituric acid reactive substances) and specific activity of the main enzymatic antioxidant defense (superoxide dismutase). Our results showed a marked decrease in both oxidative damage and antioxidant activity in individuals from larger groups, highlighting a beneficial effect of group size on individuals’ oxidative balance. We discussed the possibility that these physiological benefits originate from social thermoregulation alleviating the cost of hibernation. This study extends our understanding of the proxi- mate factors underpinning the evolution of sociality and opens up novel perspectives within the field of evolutionary ecology.
- typdoc
- Journal articles
- DOI
- DOI : 10.1093/beheco/arw114
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- titre
- Transcriptomic data analysis and differential gene expression of antioxidant pathways in king penguin juveniles (Aptenodytes patagonicus) before and after acclimatization to marine life
- auteur
- Benjamin Rey, Cyril Dégletagne, Claude Duchamp
- article
- Data in Brief, 2016, 9, pp.549-555. ⟨10.1016/j.dib.2016.09.021⟩
- resume
- In this article, we present differentially expressed gene profiles in the pectoralis muscle of wild juvenile king penguins that were either naturally acclimated to cold marine environment or experimentally immersed in cold water as compared with pen- guin juveniles that never experienced cold water immersion. Transcriptomic data were obtained by hybridizing penguins total cDNA on Affymetrix GeneChip Chicken Genome arrays and analyzed using maxRS algorithm, “Transcriptome analysis in non-model species: a new method for the analysis of hetero- logous hybridization on microarrays” (Dégletagne et al., 2010) [1]. We focused on genes involved in multiple antioxidant pathways. For better clarity, these differentially expressed genes were clustered into six functional groups according to their role in controlling redox homeostasis. The data are related to a comprehensive research study on the ontogeny of antioxidant functions in king penguins, “Hormetic response triggers multi- faceted anti-oxidant strategies in immature king penguins (Aptenodytes patagonicus)” (Rey et al., 2016) [2]. The raw microarray dataset supporting the present analyses has been deposited at the Gene Expression Omnibus (GEO) repository under accessions GEO: GSE17725 and GEO: GSE82344.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.dib.2016.09.021
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- titre
- Hormetic response triggers multifaceted anti-oxidant strategies in immature king penguins (Aptenodytes patagonicus)
- auteur
- Benjamin Rey, Cyril Dégletagne, Jacques Bodennec, Pierre-Axel Monternier, Mathieu Mortz, Damien Roussel, Caroline Romestaing, Jean-Louis Rouanet, Jérémy Tornos, Claude Duchamp
- article
- Free Radical Biology and Medicine, 2016, 97, pp.577-587. ⟨10.1016/j.freeradbiomed.2016.07.015⟩
- resume
- Repeated deep dives are highly pro-oxidative events for air-breathing aquatic foragers such as penguins. At ␣edging, the transition from a strictly terrestrial to a marine lifestyle may therefore trigger a complex set of anti-oxidant responses to prevent chronic oxidative stress in immature penguins but these pro- cesses are still unde␣ned. By combining in vivo and in vitro approaches with transcriptome analysis, we investigated the adaptive responses of sea-acclimatized (SA) immature king penguins (Aptenodytes pa- tagonicus) compared with pre-␣edging never-immersed (NI) birds. In vivo, experimental immersion into cold water stimulated a higher thermogenic response in SA penguins than in NI birds, but both groups exhibited hypothermia, a condition favouring oxidative stress. In vitro, the pectoralis muscles of SA birds displayed increased oxidative capacity and mitochondrial protein abundance but unchanged reactive oxygen species (ROS) generation per g tissue because ROS production per mitochondria was reduced. The genes encoding oxidant-generating proteins were down-regulated in SA birds while mRNA abundance and activity of the main antioxidant enzymes were up-regulated. Genes encoding proteins involved in repair mechanisms of oxidized DNA or proteins and in degradation processes were also up-regulated in SA birds. Sea life also increased the degree of fatty acid unsaturation in muscle mitochondrial membranes resulting in higher intrinsic susceptibility to ROS. Oxidative damages to protein or DNA were reduced in SA birds. Repeated experimental immersions of NI penguins in cold-water partially mimicked the effects of acclimatization to marine life, modi␣ed the expression of fewer genes related to oxidative stress but in a similar way as in SA birds and increased oxidative damages to DNA. It is concluded that the multi- faceted plasticity observed after marine life may be crucial to maintain redox homeostasis in active tissues subjected to high pro-oxidative pressure in diving birds. Initial immersions in cold-water may initiate an hormetic response triggering essential changes in the adaptive antioxidant response to marine life.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.freeradbiomed.2016.07.015
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-

- titre
- Synthesising the trait information of European Chironomidae (Insecta: Diptera): Towards a new database
- auteur
- Sonia Serra, Fernando Cobo, Manuel A. S. Graça, Sylvain Dolédec, João Feio Maria
- article
- Ecological Indicators, 2016, 61, pp.282-292. ⟨10.1016/j.ecolind.2015.09.028⟩
- resume
- Chironomidae are among the most conspicuous and ecological diverse group of freshwater invertebrates. They may dominate unimpacted communities in abundance and biomass, accounting for more than 50% of macroinvertebrate species in standing and flowing waters. In deep zones of eutrophic lakes and highly human-impacted streams, they are often the only family of aquatic insects remaining. In bioassessment programmes, Chironomids are often identified at the family and subfamily levels, due to difficulties in the taxonomic identification of larvae resulting from a high intrinsic morphological similarity. This may potentially result in bias as, similarly to Ephemeroptera, Trichoptera or Plecoptera, Chironomidae species, which are replaced along natural and human-impacted gradients due to differences in their ecological requirements. Recently, multiple trait-based approaches have been proposed to complement taxonomic- based assessment of streams and rivers using macroinvertebrates. However, the lack of specific trait information for Chironomidae prevents their use in the functional assessment of communities. Therefore, here, we aimed to: (1) develop a trait database for European Chironomidae genera that can be used in future bioassessment and ecological studies; (2) evaluate, by multivariate analyses, whether our new database provides additional information on Chironomidae compared to the trait information provided in the commonly used European trait database (Tachet et al., 2010); and (3) determine whether the new information on Eltonian traits (proxy to biological traits) translates the most accepted phylogenetic relationships among Chironomidae subfamilies. We gathered information on 744 species and 178 genera, for 37 traits covering 186 trait categories, and found substantial differences between our database and the commonly used European trait database. In addition, available information on traits was not always in agreement with phylogenetic relationships among subfamilies. Orthocladiinae and Chironominae which are considered sister groups in evolutionary terms actually showed confident trait relatedness based on Eltonian traits tree while the remaining relationships between subfamilies are questionable. In addition, different traits can occur in closely related taxa depending on the environmental drivers operating on their habitats. Our study reveals that the usually accepted redundancy within the Chironomidae family and subfamilies must be a product of averaging the information from finer taxonomic resolution added to the substantial lack of information for this insect group.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.ecolind.2015.09.028
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- titre
- Hydraulic characterization and hydrological behaviour of a pilot permeable pavement in an urban centre, Brazil
- auteur
- Artur Paiva Coutinho, Laurent Lassabatère, Suzana Montenegro, Antonio Celso Dantas Antonino, Rafaël Angulo-Jaramillo, Jaime Cabral
- article
- Hydrological Processes, 2016, ⟨10.1002/hyp.10985⟩
- typdoc
- Journal articles
- DOI
- DOI : 10.1002/hyp.10985
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- titre
- Urban groundwater age modeling under unconfined condition – Impact of underground structures on groundwater age: Evidence of a piston effect
- auteur
- Guillaume Attard, Yvan Rossier, Laurent Eisenlohr
- article
- Journal of Hydrology, 2016, 535, pp.652-661. ⟨10.1016/j.jhydrol.2016.02.034⟩
- resume
- In this paper, underground structures are shown to have a major influence on the groundwater mean age distribution described as a dispersive piston effect. Urban underground development does not occur with- out impacts on subsoil resources. In particular, groundwater resources can be vulnerable and generate disturbances when this space is exploited. Groundwater age spatial distribution data are fundamental for resource management as it can provide operational sustainability indicators. However, the application of groundwater age modeling is neglected regarding the potential effect of underground structures in urban areas. A three dimensional modeling approach was conducted to quantify the impact of two under- ground structures: (1) an impervious structure and (2) a draining structure. Both structures are shown to cause significant mixing processes occurring between shallow and deeper aquifers. The design technique used for draining structures is shown to have the greatest impact, generating a decrease in mean age of more than 80% under the structure. Groundwater age modeling is shown to be relevant for highlighting the role played by underground structures in advective–dispersive flows in urban areas.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.jhydrol.2016.02.034
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- titre
- Characterization of a genotoxicity biomarker in three-spined stickleback (Gasterosteus aculeatus L.): Biotic variability and integration in a battery of biomarkers for environmental monitoring.
- auteur
- Raphaël Santos, Aude Joyeux, Olivier Palluel, Mélissa Palos-Ladeiro, Aurélien Besnard, Christophe Blanchard, Jean-Marc Porcher, Sylvie Bony, Alain Devaux, Wilfried Sanchez
- article
- Environmental Toxicology, 2016, 31 (4), pp.415-426. ⟨10.1002/tox.22055⟩
- resume
- As a large array of hazardous substances exhibiting genotoxicity are discharged into surface water, this work aimed at assessing the relevance of adding a genotoxicity biomarker in a battery of biomarkers recently developed in the model fish three-spined stickleback (Gasterosteus aculeatus). First the confounding influence of gender, body length, and season (used as a proxy of age and of the fish reproductive status, respectively) on the level of primary DNA damage in erythrocytes was investigated in wild sticklebacks. Then, the genotoxity biomarker was included in a large battery of biomarkers assessing xenobiotic biotransformation, oxidative stress and neurotoxicity, and implemented in five sites. Gender, age and reproductive status did not influence DNA damage level in fish from the reference site. A significant relationship between the level of primary DNA damage and fish length (as a proxy of age also correlated to the season) was highlighted in the contaminated site. Among all biomarkers investigated in the field, the level of DNA damage was one of the four most discriminating biomarkers with EROD, catalase activity and the level of lipid peroxidation representing together 75.40% of the discriminating power in sampled fish. The level of DNA damage was correlated to the EROD activity and to the level of peroxidation, which mainly discriminated fish from sites under urban pressure. Finally, Integrated Biomarker Response indexes (IBRv2), which were calculated with the whole biomarker response dataset exhibited higher values in the Reveillon (9.62), the Scarpe and Rhonelle contaminated sites (5.11 and 4.90) compared with the two reference sites (2.38 and 2.55). The present work highlights that integration of a genotoxicity biomarker in a multiparametric approach is relevant to assess ecotoxicological risk in freshwater aquatic organisms.
- typdoc
- Journal articles
- DOI
- DOI : 10.1002/tox.22055
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- titre
- Unsustainable landscapes of deforested Amazonia: An analysis of the relationships among landscapes and the social, economic and environmental profiles of farms at different ages following deforestation
- auteur
- Patrick Lavelle, Sylvain Dolédec, Xavier Arnauld de Sartre, Thibaud Decaëns, Valery Gond, Michel Grimaldi, Oszwald Johan, Bernard Hubert, Bertha Ramirez, Iran Veiga, Simao de Souza, William Santos de Assis, Fernando Michelotti, Marlucia Martins, Alexander Feijoo, Pierre P. Bommel, Edna Castaneda, Patricia Chacon, Thierry Desjardins, Florence F. Dubs, Erika Gordillo, Edward Guevara, Steven Fonte, Maria del Pilar Hurtado, Philippe Léna, Tamara Lima, Raphaël Marichal, Danielle Mitja, Izildinha Miranda, Tupac Otero, Praxedes Catarina, René R. Poccard, Pascale de Robert, Gamaliel Rodriguez, Catalina Sanabria, Stéphanie Tselouiko, Alexander Velasquez, Velasquez Elena, Jaime Velasquez
- article
- Global Environmental Change, 2016, 40, pp.137-155. ⟨10.1016/j.gloenvcha.2016.04.009⟩
- resume
- In Amazonia, our knowledge of the trade-offs and possible thresholds in the relationships among social, economic and environmental parameters remains quite limited and hinders the design of sustainable socio-environmental systems. To fill this gap, we analyzed relationships among landscape metrics, socio- economic patterns, biodiversity and soil-based ecosystem services within a total of 51 farms located at 6 sites of the Colombian and Brazilian Amazon. Farms were representative of an initial set of 274 and they represented colonization ages from 10 to 80 years and a range of public policies found in the region. Two farms were abandoned in Colombia for local reasons. Cluster analysis separated farms in 7 types of production systems according to 5 main criteria (size of the farm, human capital, incomes, farm products and production intensity) selected from an initial set of 18 criteria. Biodiversity was summarized into a composite index Bd built with data from 8 different groups: trees, shrubs, grasses and forbs, birds, Saturnidae and Sphingidae moths, Drosophilidae, earthworms and ants. Provision of ecosystem services was quantified by a composite indicator of 6 sub- indicators of soil hydrological functions, C storage and chemical fertility. Increasing intensity of production systems was linked to a significant decrease of indicators of natural capital biodiversity (Bd) and soil based ecosystem services (Es) with 20% and 37.3% variance explained, respectively. No relationship was observed between production systems and an indicator of human wellbeing (Sb) based on a set of 5 criteria identified with the farmers. Findings indicate that early colonizers migrate when a certain level of development has been achieved (as a result of their activities) and are replaced by wealthier populations. An overall indicator of sustainability (Su) – that combines production efficiency (Ep), Sb, Bd and Es indices (ranging from 0.1–1.0) – decreases significantly with the landscape intensification (Li) with 18.7% variance directly explained by this relationship. Su was also significantly related to production systems (36.4% variance explained): while this indicator remained relatively stable with a value of 0.5 across the early and intermediate phases following deforestation, it dropped down considerably (0.2) for production systems based on cattle ranching on highly degraded pastures with less than 2% forest cover remaining. Restoration with sylvopastoral systems allowed some farms of this former group to increase sustainability to a value of 0.35 after less than 5 years. Agroforestry systems on sites deforested at the same time maintained values around 0.5, as they allowed the maximum production efficiencies and maintained relatively high values of the Biodiversity (Bd) and Ecosystem services (Es) indexes. This is evidence that beyond the general negative trade-off between human development and natural capital observed in Amazonia, agro ecological options to revert the trend are quite promising. A general methodological approach for the reconstruction of sustainable landscapes in farms of the deforested Amazonian region is proposed as a conclusion.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.gloenvcha.2016.04.009
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- titre
- Feasibility of using a translucid inorganic hydrogel to build a biosensor using immobilized algal cells
- auteur
- Claude Durrieu, Yannis Ferro, Mercedes Perullini, Antoine Gosset, Matias Jobbagy, Sara A. Bilmes
- article
- Environmental Science and Pollution Research, 2016, 23, pp.9-13. ⟨10.1007/s11356-015-5023-4⟩
- resume
- Anthropic activities generate contaminants, as pes- ticides and other pollutants, in the aquatic environment which present a real threat to ecosystems and human health. Thus, monitoring tools become essential for water managers to de- tect these chemicals before the occurrence of adverse effects. In this aim, algal cell biosensors, based on photosystem II activity measurement, have been designed for several years in previous studies. In this work, we study a new immobiliza- tion technique of algal cells in the aim of improving the per- formance of these biosensors. Immobilization was here achieved by encapsulation in a hybrid alginate/silica translucid hydrogel. The feasibility of this process was here assessed, and the biosensor designed was tested on the detec- tion of chemicals in urban rainwaters.
- typdoc
- Journal articles
- DOI
- DOI : 10.1007/s11356-015-5023-4
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-

- titre
- Offspring reaction norms shaped by parental environment: interaction between within- and trans-generational plasticity of inducible defenses
- auteur
- Émilien Luquet, Juliette Tariel-Adam
- article
- BMC Evolutionary Biology, 2016, 16 (209), pp.1-10. ⟨10.1186/s12862-016-0795-9⟩
- resume
- Background: Within-generational plasticity (WGP) and transgenerational plasticity (TGP) are mechanisms allowing rapid adaptive responses to fluctuating environments without genetic change. These forms of plasticity have often been viewed as independent processes. Recent evidence suggests that WGP is altered by the environmental conditions experienced by previous generations (i.e., TGP). In the context of inducible defenses, one of the most studied cases of plasticity, the WGP x TGP interaction has been poorly investigated. Results: We provide evidence that TGP can alter the reaction norms of inducible defenses in a freshwater snail. The WGP x TGP interaction patterns are trait-specific and lead to decreased slope of reaction norms (behaviour and shell thickness). Offspring from induced parents showed a higher predator avoidance behaviour and a thicker shell than snails from non-induced parents in no predator-cue environment while they reached similar defenses in predator-cue environment. The WGP x TGP interaction further lead to a switch from a plastic towards a constitutive expression of defenses for shell dimensions (flat reaction norm). Conclusions: WGP-alteration by TGP may shape the adaptive responses to environmental change and then has a substantial importance to understand the evolution of plasticity.
- typdoc
- Journal articles
- DOI
- DOI : 10.1186/s12862-016-0795-9
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-

- titre
- Contrasting patterns of environmental fluctuation contribute to divergent life histories among amphibian populations
- auteur
- Hugo Cayuela, Dragan Arsovski, Jean-Marc Thirion, Eric Bonnaire, Julian Pichenot, Sylvain Boitaud, Anne-Lise Brison, Claude Miaud, Pierre Joly, Aurélien Besnard
- article
- Ecology, 2016, 97 (4), pp.980-991. ⟨10.1890/15-0693.1⟩
- resume
- Because it modulates the fitness returns of possible options of energy expenditure at each ontogenetic stage, environmental stochasticity is usually considered a selective force in driving or constraining possible life histories. Divergent regimes of envi- ronmental fluctuation experienced by populations are expected to generate differences in the resource allocation schedule between survival and reproductive effort and outputs. To our knowledge, no study has previously examined how different regimes of stochastic variation in environmental conditions could result in changes in both the temporal variation and mean of demographic parameters, which could then lead to intraspecific variation along the slow–fast continuum of life history tactics. To investigate these issues, we used capture–recapture data collected on five populations of a long-lived amphibian (Bombina variegata) experiencing two distinct levels of stochastic environmental variation: (1) constant availability of breeding sites in space and time (predictable environment), and (2) variable spatio-temporal availability of breeding sites (unpredictable environment). We found that female breeding propensity varied more from year to year in unpredictable than in pre- dictable environments. Although females in unpredictable environments produced on average more viable offspring per year, offspring production was more variable between years. Survival at each ontogenetic stage was slightly lower and varied significantly more from year to year in unpredictable environments. Taken together, these results confirm that increased environmental stochasticity can modify the resource allocation schedule between survival and reproductive effort and outputs and may lead to intraspecific variation along the slow–fast continuum of life history tactics.
- typdoc
- Journal articles
- DOI
- DOI : 10.1890/15-0693.1
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- titre
- Substrate heterogeneity in␣uences the trait composition of stream insect communities: an experimental in situ study
- auteur
- Silvia Milesi, Sylvain Dolédec, Adriano Melo
- article
- Freshwater Science, 2016, 35 (4), pp.1321-1329. ⟨10.1086/688706⟩
- resume
- Local distribution of stream insects is influenced by abiotic factors, such as substrate heterogeneity and amount of organic matter. We evaluated the influence of substrate heterogeneity on the functional structure and diversity of stream macroinvertebrate communities based on 4 traits: feeding habits, body size, body shape, and attachment to substrate. Heterogeneous substrate supported communities with higher functional diversity and richness than did homogeneous substrate. In addition, communities on heterogeneous substrate had more predators, shredders, filterer–collectors, and organisms with a large body size than did homogeneous substrate. In contrast, communities on homogeneous substrate had predominantly small organisms, case-builders, and scrapers. Our results suggest that in natural habitats, substrate heterogeneity selects specific combinations of traits especially related to size and feeding habit, which have strong implications for stream ecosystem functioning. As a result, one may anticipate that homogenization of stream bottom substrate associated with human activities should result in a reduction or loss of important functions linked, e.g., to the processing of organic matter, which should greatly affect the stream ecosystem.
- typdoc
- Journal articles
- DOI
- DOI : 10.1086/688706
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- titre
- Fluctuating versus constant temperatures: effects on metabolic rate and oxidative damages in freshwater crustacean embryos
- auteur
- Natacha Foucreau, Charly Jehan, Martin Lawniczak, Frédéric Hervant
- article
- Canadian Journal of Zoology, 2016, 94, pp.591-598 ⟨10.1139/cjz-2015-0114⟩
- resume
- Rising temperatures will pose a major threat, notably for freshwater ecosystems, in the decades to come. Temperature, a major environmental factor, affects organisms’ physiology and metabolism. Most studies of temperature effect address constant thermal regime (CTR), whereas organisms are exposed to fluctuating thermal regime (FTR) in their natural environ- ments. In addition, previous works have predominantly addressed issues of thermal tolerance in adults rather than in early life stages. Therefore, for the first time to our knowledge, we aimed to investigate the influence of thermal conditions, either FTR or CTR, on the physiology of the crustacean amphipod Gammarus roeseli Gervais, 1835 at different embryonic stages. We measured the metabolic rate and the TBARS (thiobarbituric acid reactive substances) body content (to assess the level of oxidative damage). Oxygen consumption rate strongly increased throughout embryo development, whereas oxidative damages did not clearly change. In addition, the embryos tended to consume oxygen equally but displayed less oxidative damage when developing under FTR compared with developing under CTR. Moreover, our results revealed that fluctuating temperatures (and especially the existence of a colder (nonstressful) period during the day) could allow cell-damage repairs, and therefore, allow G. roeseli embryos to ensure good development by implementing an efficient protection response against oxidative stress.
- typdoc
- Journal articles
- DOI
- DOI : 10.1139/cjz-2015-0114
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- titre
- High-precision 34S/32S measurements in vertebrate bioapatites using purge-and-trap elemental analyser/isotope ratio mass spectrometry technology
- auteur
- Jean Goedert, François Fourel, Romain Amiot, Laurent Simon, Christophe Lecuyer
- article
- Rapid Communications in Mass Spectrometry, 2016, 30 (18), pp.2002-2008. ⟨10.1002/rcm.7690⟩
- resume
- RATIONALE: In ecological studies, the sulfur isotope compositions (à34S values) of soft tissues (e.g. hair, skin, nail, muscle, collagen) allow the determination of both past and present-day living environments of organisms. However, technical limitations have so far prevented reliable sulfur isotope analyses of minerals having low sulfur content, such as bioapatite, which is the crystalline component of skeletal tissues. The development of ‘purge-and-trap’ technology in elemental analysers recently demonstrated new possibilities to solve some of those technical difficulties. METHODS: We have used a VarioPYROcube elemental analyser (EA) equipped with ‘purge-and-trap’ technology, interfaced in continuous flow mode to an Isoprime 100 isotope ratio mass spectrometer, to measure the sulfur isotope compositions of bioapatite samples. We first characterised a working calibrated material of chemical composition close to those of our samples, the low-S bearing phosphorite BCR32, against the two à34SV-CDT reference-calibrated materials, NBS-127 and IAEA-SO-5. We have confirmed a 34SV-CDT value of +18.4‰ (1 = 0.5; n = 18) in agreement with the previously published value. Using BCR32 as a compositional and isotopic reference material, we have then measured the à34SV-CDT values of various bioapatite tissues (bone, dentine and enamel) from both modern and fossil vertebrates living in different environments (marine, freshwater and terrestrial). RESULTS: Our results demonstrate the capacity of this analytical setup to measure the à34SV-CDT values of low-S bioapatite samples (0.14 to 1.19 wt%) with a good analytical precision (1 = 0.5; n = 14). Our results also show that the à34SV-CDT values of modern and fossil vertebrate bioapatites allow discrimination between marine environments and freshwater or terrestrial ones. CONCLUSIONS: Sulfur isotope analysis of bioapatite has great potential to track the living environment of extinct vertebrates for which only fossilised bones or teeth have been preserved.
- typdoc
- Journal articles
- DOI
- DOI : 10.1002/rcm.7690
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- titre
- Clonal growth architecture and spatial dynamics of 10 species of the genus Potamogeton across different habitats in Kashmir valley, India.
- auteur
- Aijaz Hassan Ganie, Zafar A. Reshi, B.A. Wafai, Sara Puijalon
- article
- Hydrobiologia, 2016, 767, pp.289-299. ⟨10.1007/s10750-015-2509-5⟩
- resume
- The plasticity in clonal architecture may enable plants to effectively respond to environmental constraints and to enhance species ecological niche breadth but its role in plant tolerance to water flow is poorly documented. The present study was carried out to determine whether the clonal architecture varies with respect to water flow in 10 species of the genus Potamogeton colonizing habitats differing by flow conditions. For these 10 species, the traits describing clonal architecture were measured on individuals sampled in natural sites and plasticity in clonal architecture was examined in a common garden growth experiment. The clonal growth architecture did not vary significantly in the species which inhabit either standing (P. lucens, P. natans, and P. pusillus) or running water (P. amblyphyllus and P. berchtoldii). However, the species inhabiting both standing as well as running waters (P. crispus, P. nodosus, P. pectina- tus, P. perfoliatus, and P. wrightii) showed consider- able and significant variation in clonal growth architecture across these habitats. Transplantation experiment revealed that clonal architecture observed between the plants under different conditions is plastic and not due to genetic differentiation. The present study demonstrated that plasticity in the clonal architecture may enable these species to inhabit stressful conditions of flowing water.
- typdoc
- Journal articles
- DOI
- DOI : 10.1007/s10750-015-2509-5
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- titre
- Triassic Kykloxylon wood (Umkomasiaceae, Gymnospermopsida) from Skinner Ridge, northern Victoria Land, East Antarctica
- auteur
- Changhwan Oh, Tae-Yoon Park, Jusun Woo, Benjamin Bomfleur, Marc Philippe, Anne-Laure Decombeix, Young-Hwan G. Kim, Jong Ik Lee
- article
- Review of Palaeobotany and Palynology, 2016, 233, pp.104-114. ⟨10.1016/j.revpalbo.2016.07.006⟩
- resume
- During the ␣rst Korea Antarctic Geological Expedition (KAGEX I, 2013/2014), fossil wood was collected from the Triassic ␣uvial deposits of the Beacon Supergroup at Skinner Ridge in northern Victoria Land, Antarctica. The material is coali␣ed and partially silici␣ed; most specimens are slightly compressed due to burial compaction. In spite of this imperfect preservation, anatomical features of both the xylem and the pith could be observed in some specimens. The xylem displays prominent growth rings and usually araucarioid or somewhat mixed- type radial pitting with some abnormal rings partly composed of parenchymatous tissues. Some specimens also have a wood cylinder that is divided radially by parenchymatous zones. These anatomical features indicate a systematic af␣nity with Kykloxylon Mey.-Berth., T.N.Taylor et Ed.L.Taylor, a characteristic wood type of the Umkomaciaceae, which ␣ourished throughout Gondwana during the Triassic. The Kykloxylon specimens in this study represent the only wood fossil taxon in the Triassic of Victoria Land, except for a dubious report of Antarcticoxylon Seward in 1914. This may indicate a low diversity of Triassic wood fossils in this area, as in other parts of Antarctica. On the contrary, diverse other gymnosperm organs are known to occur in the Triassic of Antarctica. This low diversity of wood taxa compared to the various plant organs in the Triassic of Antarctica is remarkable. We hypothesize three major reasons for this: 1) the overall structural uniformity of gymnosperm wood compared to other vegetative and especially reproductive organ diversity; 2) the overwhelming dominance of corystosperm plants, with a minor component of voltzialean conifers in the canopy-forming forest vegetation during the Triassic in Antarctica; and 3) the very few systematic studies of fossil wood compared to other plant macrofossils.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.revpalbo.2016.07.006
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- titre
- AM fungi patchiness and the clonal growth of Glechoma hederacea in heterogeneous environments
- auteur
- Nathan Vannier, Anne‐kristel Bittebière, Philippe Vandenkoornhuyse, Cendrine Mony
- article
- Scientific Reports, 2016, 6 (1), pp.37852. ⟨10.1038/srep37852⟩
- resume
- The effect of AM fungi spatial distribution on individual plant development may determine the dynamics of the whole plant community. We investigated whether clonal plants display, like for other resources, a foraging or a specialization response, to adapt to the distribution of AM fungi. Two separate experiments were done to investigate the response of Glechoma hederacea to a heterogeneous distribution of a mixture of 3AM fungi species, and the effects of each species on colonization and allocation traits. No specialization and a limited foraging response to the heterogeneous distribution of AM fungi was observed. An effect of the AM fungal species on plant mass allocation and ramet production, but not on spacer length, was detected. Two possible explanations are proposed: (i) the plant’s responses are buffered by differences in individual effects of the fungal species or their root colonization intensity. (ii) the initial heterogeneous distribution of AM fungi is perceived as homogeneous by the plant either by reduced physiological integration or due to the transfer of AM fungi propagules through the stolons. Microscopic and DNA sequencing analyses provided evidence of this transfer, thus demonstrating the role of stolons as dispersal vectors of AM fungi within the plant clonal network.
- typdoc
- Journal articles
- DOI
- DOI : 10.1038/srep37852
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-

- titre
- Mechanism of biological denitrification inhibition: procyanidins induce an allosteric transition of the membrane-bound nitrate reductase through membrane alteration
- auteur
- Clément Bardon, Poly Franck, Florence Piola, Muriel Pacton, Gilles Comte, Guillaume Meiffren, Feth El Zahar Haichar
- article
- FEMS Microbiology Ecology, 2016, 92 (1-13), pp.3-11. ⟨10.1093/femsec/fiw034⟩
- resume
- Recently, it has been shown that procyanidins from Fallopia spp. inhibit bacterial denitrification, a phenomenon called biological denitrification inhibition (BDI). However, the mechanisms involved in such a process remain unknown. Here, we investigate the mechanisms of BDI involving procyanidins, using the model strain Pseudomonas brassicacearum NFM 421. The aerobic and anaerobic (denitrification) respiration, cell permeability and cell viability of P. brassicacearum were determined as a function of procyanidin concentration. The effect of procyanidins on the bacterial membrane was observed using transmission electronic microscopy. Bacterial growth, denitrification, NO3- and NO2-reductase activity, and the expression of subunits of NO3- (encoded by the gene narG) and NO2-reductase (encoded by the gene nirS) under NO3 or NO2 were measured with and without procyanidins. Procyanidins inhibited the denitrification process without affecting aerobic respiration at low concentrations. Procyanidins also disturbed cell membranes without affecting cell viability. They specifically inhibited NO3- but not NO2-reductase. Pseudomonas brassicacearum responded to procyanidins by over-expression of the membrane-bound NO3-reductase subunit (encoded by the gene narG). Our results suggest that procyanidins can specifically inhibit membrane-bound NO3-reductase inducing enzymatic conformational changes through membrane disturbance and that P. brassicacearum responds by over-expressing membrane-bound NO3-reductase. Our results lead the way to a better understanding of BDI.
- typdoc
- Journal articles
- DOI
- DOI : 10.1093/femsec/fiw034
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- titre
- Lipid-induced thermogenesis is up-regulated by the first cold-water immersions in juvenile penguins
- auteur
- Loïc Teulier, Benjamin Rey, Jérémy Tornos, Marion Le Coadic, Pierre-Axel Monternier, Aurore Bourguignon, Virginie Dolmazon, Caroline Romestaing, Jean-Louis Rouanet, Claude H. B. Duchamp, Damien Roussel
- article
- Journal of Comparative Physiology B, 2016, 186, pp.639-650. ⟨10.1007/s00360-016-0975-3⟩
- resume
- The passage from shore to marine life is a critical step in the development of juvenile penguins and is characterized by a fuel selection towards lipid oxida- tion concomitant to an enhancement of lipid-induced ther- mogenesis. However, mechanisms of such thermogenic improvement at fledging remain undefined. We used two different groups of pre-fledging king penguins (Apteno- dytes patagonicus) to investigate the specific contribution of cold exposure during water immersion to lipid metabo- lism. Terrestrial penguins that had never been immersed in cold water were compared with experimentally cold-water immersed juveniles. Experimentally immersed penguins underwent ten successive immersions at approximately 9–10 °C for 5 h over 3 weeks. We evaluated adaptive ther- mogenesis by measuring body temperature, metabolic rate and shivering activity in fully immersed penguins exposed to water temperatures ranging from 12 to 29 °C. Both never-immersed and experimentally immersed penguins were able to maintain their homeothermy in cold water, exhibiting similar thermogenic activity. In vivo, perfusion of lipid emulsion at thermoneutrality induced a twofold larger calorigenic response in experimentally immersed than in never-immersed birds. In vitro, the respiratory rates and the oxidative phosphorylation efficiency of isolated muscle mitochondria were not improved with cold-water immersions. The present study shows that acclimation to cold water only partially reproduced the fuel selection towards lipid oxidation that characterizes penguin acclima- tization to marine life.
- typdoc
- Journal articles
- DOI
- DOI : 10.1007/s00360-016-0975-3
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- titre
- Modelling algae-duckweed interaction under chemical pressure within a laboratory microcosm
- auteur
- Dominique Lamonica, Bernard Clement, Sandrine Charles, Christelle Lopes
- article
- Ecotoxicology and Environmental Safety, 2016, 128, pp.252-65. ⟨10.1016/j.ecoenv.2016.02.008⟩
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.ecoenv.2016.02.008
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- titre
- Trophic ecology of groundwater species reveals specialization in a low-productivity environment
- auteur
- Clémentine François, Florian Mermillod-Blondin, Florian Malard, François Fourel, Christophe Lecuyer, Christophe Jean Douady, Laurent Simon
- article
- Functional Ecology, 2016, 30, pp.262-273. ⟨10.1111/1365-2435.12484⟩
- resume
- 1. Identifying feeding strategies at lower bounds of habitat productivity is fundamental to understand the relationship between energy availability and trophic specialization. Low pro- ductivity is expected to severely constrain trophic specialization because organisms may no longer be able to fulfil their energy requirements by feeding on a reduced set of resources. However, species living in low-productivity habitats often exhibit particular biological traits such as low metabolic rates and high food-finding abilities, which may release constraints on trophic specialization. 2. In the present study, we used carbon (C) and nitrogen (N) stable isotopes to measure the degree of trophic specialization in two species of isopods (Proasellus valdensis and Proasellus cavaticus) living in groundwater, one of the most energy-limited environments on earth. Fun- damental specialization was obtained from a 13C/15N-labelling experiment in the laboratory: we measured separately the carbon and nitrogen assimilation rates of the two species across the three food sources encountered in their natural cave habitats (fine and coarse particulate organic matter and sedimentary biofilm). Then, for each species, we tested for variation in diet composition among individuals and populations by quantifying the relative contribution of the three food sources to the diet of multiple individuals within 5 cave populations. 3. The labelling experiment showed that both species assimilated about 10 times more carbon and at least 4 times more nitrogen from sedimentary biofilm than from both forms of particu- late organic matter. Field samplings showed that sedimentary biofilm made up, on average, 83% of the diet of isopods. Moreover, we found almost no variation in diet among individuals of a cave population as well as among cave populations within species. 4. This study provides the first evidence of a high degree of trophic specialization in a low- productivity cave environment. Both species exhibited a strong fundamental specialization on sedimentary biofilm and most probably fed selectively on this food source in their natural environment. Our findings challenge the prediction that species would adopt generalist feeding strategies at lower bounds of habitat productivity.
- typdoc
- Journal articles
- DOI
- DOI : 10.1111/1365-2435.12484
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- titre
- Proposal to optimize ecotoxicological evaluation of wastewater treated by conventional biological and ozonation processes
- auteur
- Adriana Wigh, Alain Devaux, Vanessa Brosselin, Adriana Gonzalez-Ospina, Bruno Domenjoud, Selim Ait-Aissa, Nicolas Creusot, Antoine Gosset, Christine Bazin, Sylvie Bony
- article
- Environmental Science and Pollution Research, 2016, 23 (4), pp.3008-3017. ⟨10.1007/s11356-015-5419-1⟩
- resume
- A mixture of urban and hospital effluents (50 % v/v) was evaluated for ecotoxicity with an advanced bioassay battery. Mixed effluents were tested before any treatment, af- ter biological treatment alone, and after biological treatment followed by a tertiary ozonation (15 mg O3/L). Laying a high value on the continuance of organisms’ fitness, essential to preserve a healthy receiving ecosystem, the main objective of this study was to combine normalized bioassays with newly developed in vivo and in vitro tests in order to assess alteration of embryo development, growth and reproduction, as well as genotoxic effects in aquatic organisms exposed to complex wastewater effluents. Comparison of the bioassays sensitivity was considered. Contrary to the lack of toxicity observed with normalized ecotoxicity tests, endpoints measured on zebrafish embryos such as developmental abnormalities and genotoxicity demonstrated a residual toxicity in wastewater both after a biological treatment followed or not by a tertiary O3 treatment. However, the ozonation step allowed to alleviate the residual endocrine disrupting potential measure in the bi- ologically treated effluent. This study shows that normalized bioassays are not sensitive enough for the ecotoxicological evaluation of wastewaters and that there is a great need for the development of suitable sensitive bioassays in order to characterize properly the possible residual toxicity of treated effluents.
- typdoc
- Journal articles
- DOI
- DOI : 10.1007/s11356-015-5419-1
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- titre
- Detection of a global aquatic invasive amphibian, Xenopus laevis, using environmental DNA
- auteur
- Jean Secondi, Tony Dejean, Alice Valentini, Benjamin Audebaud, Claude Miaud
- article
- Amphibia-Reptilia, 2016, 37 (1), pp.131-136. ⟨10.1163/15685381-00003036⟩
- resume
- Detection is crucial in the study and control of invasive species but it may be limited by methodological issues. In amphibians, classical survey techniques exhibit variable detection probability depending on species and are often constrained by climatic conditions often requiring several site visits. Furthermore, detection may be reduced at low density because probability capture (passive traps), or activity (acoustic surveys) drop. Such limits may impair the study of invasive species because low density is typical of the onset of colonisation on a site. In the last few years, environmental DNA (eDNA) methods have proved their ability to detect the presence of aquatic species. We developed here an eDNA method to detect Xenopus laevis in ponds. This austral African species is now present worldwide because of its use in biology and as a pet. Populations have settled and expanded on several continents so that it is now considered as one of the major invasive amphibians in the World. We detected the presence of X. laevis at density as low as 1 ind/100 m2 and found a positive relationship between density in ponds and rate of DNA amplification. Results show that eDNA can be successfully applied to survey invasive populations of X. laevis even at low density in order to confirm suspected cases of introduction, delimit the expansion of a colonized range, or monitor the efficiency of a control program.
- typdoc
- Journal articles
- DOI
- DOI : 10.1163/15685381-00003036
- Accès au bibtex
-
-

- titre
- Impacts of Climate Change on the Global Invasion Potential of the African Clawed Frog Xenopus laevis
- auteur
- Flora Ihlow, Julien Courant, Jean Secondi, Anthony Herrel, Rui Rebelo, Measey G.J., Francesco Lillo, André de Villiers, Solveig Vogt, Charlotte de Busschere, Thierry Backeljau, Dennis Rödder
- article
- PLoS ONE, 2016, 11 (6:e0154869.), pp.1-19. ⟨10.1371/journal.pone.0154869⟩
- resume
- By altering or eliminating delicate ecological relationships, non-indigenous species are con- sidered a major threat to biodiversity, as well as a driver of environmental change. Global cli- mate change affects ecosystems and ecological communities, leading to changes in the phenology, geographic ranges, or population abundance of several species. Thus, predicting the impacts of global climate change on the current and future distribution of invasive species is an important subject in macroecological studies. The African clawed frog (Xenopus laevis), native to South Africa, possesses a strong invasion potential and populations have become established in numerous countries across four continents. The global invasion potential of X. laevis was assessed using correlative species distribution models (SDMs). SDMs were com- puted based on a comprehensive set of occurrence records covering South Africa, North America, South America and Europe and a set of nine environmental predictors. Models were built using both a maximum entropy model and an ensemble approach integrating eight algo- rithms. The future occurrence probabilities for X. laevis were subsequently computed using bioclimatic variables for 2070 following four different IPCC scenarios. Despite minor differ- ences between the statistical approaches, both SDMs predict the future potential distribution of X. laevis, on a global scale, to decrease across all climate change scenarios. On a conti- nental scale, both SDMs predict decreasing potential distributions in the species’ native range in South Africa, as well as in the invaded areas in North and South America, and in Australia where the species has not been introduced. In contrast, both SDMs predict the potential range size to expand in Europe. Our results suggest that all probability classes will be equally affected by climate change. New regional conditions may promote new invasions or the spread of established invasive populations, especially in France and Great Britain.
- typdoc
- Journal articles
- DOI
- DOI : 10.1371/journal.pone.0154869
- Accès au texte intégral et bibtex
-
- titre
- Nutrient and metal pollution of the eastern Gulf of Finland coastline: Sediments, macroalgae, microbiota
- auteur
- Yulia Gubelit, Yulia Polyak, Grazyna Dembska, Grazyna Pazikowska-Sapota, Lukasz Zegarowski, Dmitry Kochura, Denis Krivorotov, Elena Podgornaya, Chafik Maazouzi
- article
- Science of the Total Environment, 2016, 550, pp.806-819. ⟨10.1016/j.scitotenv.2016.01.122⟩
- resume
- The anthropogenic pollution along the coastline of the eastern Gulf of Finland was studied through a range of methods, including analyses of metal contamination in water, surface sediments, accumulated algal biomass and its correlation with resistant microbiota. According to concentrations, the main pollutants in water were copper and manganese. In␣uence of Nuclear Power Plant was remarkable in adjacent areas and was expressed in high concentrations of molybdenum, nickel, copper and other elements in the water. Relatively high concen- trations of copper, lead and zinc were found in sediments. Microbial tolerance appeared to be correlated with the concentration of the metals in sediments. Higher tolerance levels were found in sediment samples from more polluted stations. Macroalgae, which were massively developed in the coastal zone, had shown high level of metal bioaccumulation. Analyses of carbon, nitrogen and phosphorus content of algal tissues allowed the estima- tion of additional nutrient loading from accumulated decaying algal biomass on the coastal zone of the eastern Gulf of Finland. Mass development of algae in coastal area may contribute to accumulation of organic matter and associated metals. In our study the highest metal concentrations in sediments were found at the sites with dense and continuous layer of fresh and decaying macroalgal biomass, accompanied by hypoxic conditions.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.scitotenv.2016.01.122
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-
- titre
- Caractérisation de l’écotoxicité des rejets liquides des laboratoires de biologie médicale
- auteur
- Marine Philippot, Christine Bazin, Pascale Preynat-Boucher, Jean-Marc Giannoli, Yves Perrodin
- article
- Revue des Sciences de l'Eau / Journal of Water Science, 2016, 29 (3), pp.303-314. ⟨10.7202/1038929ar⟩
- resume
- Les échantillons sanguins ou urinaires prélevés dans les laboratoires de biologie médicale sont aujourd’hui dirigés vers des plateformes d’analyse centralisées permettant l’optimisation des analyses, tant sur le plan technique qu’économique. Ces plateformes sont équipées d’automates spécialisés utilisant de nombreux réactifs chimiques. Ces réactifs contiennent parfois des substances très écotoxiques qui peuvent ainsi être rejetées au réseau d’assainissement urbain sans traitement préalable. Dans le but de caractériser les dangers environnementaux liés à ces rejets liquides méconnus, un programme de caractérisation chimique et écotoxicologique a été mis en place sur les rejets d’un laboratoire pilote situé dans la région lyonnaise. Ce programme a montré la forte écotoxicité des rejets de certains automates. Il a également mis en évidence l’écotoxicité des rejets liquides traités à l’Eau de Javel dans le laboratoire, dans le but d’éliminer les germes pathogènes. Après consolidation par la réalisation de mesures sur d’autres sites, ces résultats pourront être utilisés par les responsables des plateformes en vue de l’amélioration de la gestion de leurs rejets : remplacement de certains réactifs par des composés moins écotoxiques, prétraitement de certains rejets sur le site même du laboratoire, évacuation des rejets les plus écotoxiques, ou difficilement traitables in situ , vers des filières de traitement adaptées.
- typdoc
- Journal articles
- DOI
- DOI : 10.7202/1038929ar
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-
- titre
- Carbon emission along a eutrophication gradient in temperate riverine wetlands: effect of primary productivity and plant community composition
- auteur
- Charlotte Grasset, Gwenaël Abril, Ludovic Guillard, Cécile Delolme, Gudrun Bornette
- article
- Freshwater Biology, 2016, 61 (9), pp.1405-1420. ⟨10.1111/fwb.12780⟩
- resume
- 1. Eutrophication increases primary productivity and favours the predominance of floating vegetation in wetlands. Carbon (C) fluxes in wetlands are strongly driven by primary productivity and can differ by vegetation type. However, to the best of our knowledge, the role of eutrophication in C fluxes has rarely been assessed. 2. Consequently, we aimed to measure the seasonal variation in carbon dioxide (CO2) and methane (CH4) fluxes at six aquatic sites in four temperate wetlands, ranging along a gradient of sediment total phosphorus content, and determine whether C fluxes correlate with above-ground net primary productivity (ANPP) and plant community composition along this eutrophication gradient. 3. Daytime CO2 emissions were significantly and negatively correlated with wetland net primary productivity as a result of the greater C fixation by photosynthesis during the peak of production. Conversely, CH4 emissions were significantly and positively correlated with wetland ANPP, possibly due to higher litter production and anaerobic decomposition. 4. The highest CH4 emissions were observed above floating vegetation, which favoured hypoxic conditions in the water column. CH4 emissions including ebullition were higher above macroalgal belts than above vascular plants with floating leaves. CH4 emissions without ebullition (i.e. resulting from plant transport and diffusion) better correlated with the abundance of macroalgae than with the abundance of vascular plants with floating leaves. 5. Our results suggest that eutrophication may greatly modify CO2 and CH4 emissions from wetlands through changes in vegetation type and productivity.
- typdoc
- Journal articles
- DOI
- DOI : 10.1111/fwb.12780
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-
- titre
- Does habitat unpredictability promote the evolution of a colonizer syndrome in amphibian metapopulations ?
- auteur
- Hugo Cayuela, Laurent Boualit, Dragan Arsovski, Eric Bonnaire, Julian Pichenot, Arnaud Bellec, Claude Miaud, Jean-Paul Léna, Pierre Joly, Aurélien Besnard
- article
- Ecology, 2016, 97 (10), pp.2658-2670. ⟨10.1002/ecy.1489/suppinfo⟩
- resume
- Dispersal is a central component of life history evolution. An increasing number of studies suggest that spatiotemporally variable environments may promote the evolution of “dispersal syndromes,” consisting of covariation patterns between dispersal and morphologi- cal, physiological, behavioral, and life history traits. At the interspecific scale, the “colonizer syndrome” appears to be one of the most frequently recorded associations between dispersal and life history traits, linking a high dispersal rate, high fecundity, and a short lifespan as sys- tematically combined adaptations in spatiotemporally varying environments. However, few studies have highlighted the existence of a “colonizer syndrome” at the intraspecific scale, and none have investigated how different degrees of habitat stochasticity might shape covariation patterns between dispersal and life history traits. In this study, we examined this issue in free- ranging metapopulations of the yellow-bellied toad (Bombina variegata) using capture–recap- ture data. Combining the results of this study with another recent study, we found that a high dispersal rate, high fecundity, and a short lifespan are associated in metapopulations experi- encing unpredictable environments. In contrast, a very low dispersal rate (close to zero), low fecundity and a long lifespan are associated in metapopulations occupying predictable environ- ments. We discuss these results as well as their demographic and evolutionary consequences.
- typdoc
- Journal articles
- DOI
- DOI : 10.1002/ecy.1489/suppinfo
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- titre
- In situ Comparison of Tree-Ring Responses to Climate and Population Genetics: The Need to Control for Local Climate and Site Variables
- auteur
- Johann M. Housset, Christopher Carcaillet, Martin P. Girardin, Xu Huaitong, Francine Tremblay, Yves Bergeron
- article
- Frontiers in Ecology and Evolution, 2016, 4 (123), pp.1-12. ⟨10.3389/fevo.2016.00123⟩
- resume
- Tree species responses to climate change will be greatly influenced by their evolutionary potential and their phenotypic plasticity. Investigating tree-rings responses to climate and population genetics at the regional scale is crucial in assessing the tree behavior to climate change. This study combined in situ dendroclimatology and population genetics over a latitudinal gradient and compared the variations between the two at the intra- and inter-population levels. This approach was applied on the northern marginal populations of Thuja occidentalis (eastern white-cedar) in the Canadian boreal forest. We aimed first to assess the radial growth variability (response functional trait) within populations across the gradient and to compare it with the genetic diversity (microsatellites). Second, we investigated the variability in the growth response to climate at the regional scale through the radial growth-climate relationships, and tested its correlation with environmental variables and population genetic structure. Model selection based on the Akaike Information Criteria revealed that the growth synchronicity between pairs of trees of a population covariates with both the genetic diversity of this population and the amount of precipitation (inverse correlations), although these variables only explained a small fraction of the observed variance. At the regional scale, variance partitioning and partial redundancy analysis indicate that the growth response to climate was greatly modulated by stand environmental variables, suggesting predominant plastic variations in growth-response to climate. Combining in situ dendroclimatology and population genetics is a promising way to investigate species’ response capacity to climate change in natural stands. We stress the need to control for local climate and site conditions effects on dendroclimatic response to climate to avoid misleading conclusions regarding the associations with genetic variables.
- typdoc
- Journal articles
- DOI
- DOI : 10.3389/fevo.2016.00123
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- titre
- Glyphosate and AMPA adsorption in soils: laboratory experiments and pedotransfer rules
- auteur
- Pauline Sidoli, Nicole Baran, Rafaël Angulo-Jaramillo
- article
- Environmental Science and Pollution Research, 2016, 23, pp.5733-5742. ⟨10.1007/s11356-015-5796-5⟩
- resume
- Adsorption of the herbicide glyphosate and its main metabolite AMPA (aminomethylphosphonic acid) was investigated on 17 different agricultural soils. Batch equilibration adsorption data are shown by Freundlich adsorp- tion isotherms. Glyphosate adsorption is clearly affected by equilibration concentrations, but the nonlinear AMPA adsorp- tion isotherms indicate saturation of the adsorption sites with increasing equilibrium concentrations. pHCaCl2 (i.e. experi- mental pH) is the major parameter governing glyphosate and AMPA adsorption in soils. However, considering pHCaCl2 values, available phosphate amount, and amorphous iron and aluminium oxide contents by using a nonlinear multiple regression equation, obtains the most accurate and powerful pedotransfer rule for predicting the adsorption constants for these two molecules. As amorphous iron and aluminium oxide contents in soil are not systematically determined, we also propose a pedotransfer rule with two variables—pHCaCl2 values and available phosphate amount—that remains accept- able for both molecules. Moreover, the use of the commonly measured pHwater or pHKCl values gives less accurate results compared to pHCaCl2 measurements. To our knowledge, this study is the first AMPA adsorption characterization for a sig- nificant number of temperate climate soils.
- typdoc
- Journal articles
- DOI
- DOI : 10.1007/s11356-015-5796-5
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- titre
- Increased depth to the water table during river drying decreases the resilience of Gammarus pulex and alters ecosystem function
- auteur
- Ross Vander Vorste, Florian Mermillod-Blondin, Frédéric Hervant, R. Mons, Maxence Forcellini, T. Datry
- article
- Ecohydrology, 2016, 9 (7), pp.1177-1186. ⟨10.1002/eco.1716⟩
- resume
- River drying has drastic immediate effects on benthic invertebrates, but their high resilience reduces long-term effects on biodiversity and ecosystem functions (e.g. leaf litter decomposition). The hyporheic zone (saturated sediments below the riverbed) can be a refuge for invertebrates in dry rivers and a primary source of colonists supporting population resilience following flow resumption. However, factors such as the depth to the water table below the riverbed, which could determine the quality of the hyporheic refuge, are not well understood. We explored how depth to the water table (control, −5 cm, −30 cm and completely dry) during a 1-week drying event affected the survival and return to the substrate surface (%RTS) of Gammarus pulex (Crustacea : Amphipoda) using laboratory mesocosms. We measured litter decomposition and Gammarus energy stores to examine effects on ecosystem function and energetic costs for organisms crawling deeper into the hyporheic zone. Two populations, collected from intermittent and perennial rivers, were used to evaluate inter-population variability in response to drying. Survival and %RTS were reduced by ≤39% and 52%, respectively, in the −30 cm and dry treatments, and this had consequences for decomposition (≤46% reduction). Differences between populations in %RTS were high across treatments but did not generally affect survival and decomposition. Our results suggest that increases in depth to the water table during river drying, which often result from longer drying duration and water abstraction, could reduce invertebrate resilience and litter decomposition by diminishing the role of the hyporheic zone as a source of colonists.
- typdoc
- Journal articles
- DOI
- DOI : 10.1002/eco.1716
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- titre
- Impact of art therapy (AT) on fatigue and quality of life (QoL) during adjuvant external beamirradiation (EBI) in breast cancer patients (pts): a randomized trial
- auteur
- F. Joly, D. Pasquier, C. Hanzen, N. Heutte, C. Levy, F. Le Tinier, M. Mousseau, C. Ciais, C. Murariu, M.-C. d'Almeida, V. Szymczak, C. Leon, S. Darbas, M.-P. Rousselot, S. Mineur, C. Rieux, A. Leconte, O. Rigal, B. Clarisse, D. Allouache
- article
- Annals of Oncology, 2016, 27, ⟨10.1093/annonc/mdw390.7⟩
- typdoc
- Journal articles
- DOI
- DOI : 10.1093/annonc/mdw390.7
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- titre
- Genetic integrity of European grayling (Thymallus thymallus L. 1758) population within the Vienne River drainage basin after five decades of stockings
- auteur
- Henri Persat, Karin Mattersdorfer, Stéphanie Charlat, Tamara Schenekar, Steven Weiss
- article
- Frontiers in Marine Science, 2016, 40 (1), pp.7-20. ⟨10.3389/conf.FMARS.2015.03.00149⟩
- typdoc
- Journal articles
- DOI
- DOI : 10.3389/conf.FMARS.2015.03.00149
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- titre
- Impact of cadmium on the ecdysteroids production in Gammarus fossarum
- auteur
- Sondes Abidi, Khedidja Tair Abbaci, Olivier Geffard, Moncef Boumaiza, Adeline Dumet, Jeanne Garric, Nathalie Mondy
- article
- Ecotoxicology, 2016, 25 (5), pp.880-887. ⟨10.1007/s10646-016-1645-7⟩
- resume
- Gammarus fossarum is an important test organism which is currently used as a bio-indicator as well as in ecotoxicological tests. Nevertheless, data on ecdys- teroids in endocrine toxicity test are not yet available for these species, despite its crucial role in molting and reproduction. In the present paper, ecdysteroids concen- trations were studied during the molt cycle (in females) and embryonic development in G. fossarum (Crustacea, Amphipoda) in order to propose an ecdysteroids toxicity test. Ecdysteroids levels in G. fossarum showed a single peak during premolt at stage Dl-D2. In embryos, ecdys- teroids levels progressively increased over stages 3 and 4, with peak levels at stage 4. A Cadmium toxicity test was proposed to examine if the molting and embryogenesis disturbances previously observed after cadmium exposure (Geffard et al. 2010) could be attributed to changes in ecdysteroids titers. Exposure to the different cadmium concentrations (3; 9; 300; 900 lg/l) increased ecdysteroids secretion by Y-organs in vitro, but it had no significant effect on exposed embryos (in vivo). Based on previous findings, we are led to conclude that the molting impairments in cadmium-exposed females of G. fossarum is connected to the changes in ecdysteroids concentrations.
- typdoc
- Journal articles
- DOI
- DOI : 10.1007/s10646-016-1645-7
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- titre
- All or nothing: Survival, reproduction and oxidative balance in Spotted Wing Drosophila (Drosophila suzukii) in response to cold
- auteur
- Christophe Plantamp, Katleen Salort, Patricia Gibert, Adeline Dumet, Gladys Mialdea, Nathalie Mondy, Yann Voituron
- article
- Journal of Insect Physiology, 2016, 89, pp.28-36. ⟨10.1016/j.jinsphys.2016.03.009⟩
- resume
- Winter severity and overwintering capacity are key ecological factors in successful invasions, especially in ectotherms. The integration of physiological approaches into the study of invasion processes is emerg- ing and promising. Physiological information describes the mechanisms underlying observed survival and reproductive capacities, and it can be used to predict an organism’s response to environmental per- turbations such as cold temperatures. We investigated the effects of various cold treatments on life his- tory and physiological traits of an invasive pest species, Drosophila suzukii, such as survival, fertility and oxidative balance. This species, a native of temperate Asian areas, is known to survive where cold tem- peratures are particularly harsh and has been recently introduced into Europe and North America. We found that cold treatments had a strong impact on adult survival but no effect on female’s fertility. Although only minor changes were observed after cold treatment on studied physiological traits, a strong sex-based difference was observed in both survival and physiological markers (antioxidant defences and oxidative markers). Females exhibited higher survival, reduced oxidative defences, less damage to nucleic acids, and more damage to lipids. These results suggest that D. suzukii relies on a pathway other than oxidative balance to resist cold injury. Altogether, our results provide information concerning the mech- anisms of successful invasion by D. suzukii. These findings may assist in the development of population models that predict the current and future geographic ranges of this species.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.jinsphys.2016.03.009
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- titre
- Mechanistic modelling of daphnid-algae dynamics within a laboratory microcosm
- auteur
- Dominique Lamonica, Ulysse Herbach, Frédéric Orias, Bernard Clément, Sandrine Charles, Christelle Lopes
- article
- Ecological Modelling, 2016, 320, pp.213-230. ⟨10.1016/j.ecolmodel.2015.09.020⟩
- resume
- Our study describes the functioning of a 2-L laboratory microcosm of two species, daphnids (Daphnia magna) and microalgae (Pseudokirchneriella subcapitata), in two abiotic phases (water column and sedi- ment). We modelled the dynamics of both species and their interactions using a mechanistic model based on coupled ordinary differential equations. The main processes occurring in this two-species microcosm were thus formalised, including growth and settling of algae and growth, survival and grazing of daph- nids. We estimated model parameters by Bayesian inference, using simultaneously all data from multiple experiments specifically conducted for this study. Two types of model verifications were performed: (1) internal verification to validate model structure and parameter estimation method using all data simul- taneously; and (2) external verification to validate the ability of the model to be applied under new sediment conditions. For all parameters, we obtained biologically realistic values and reasonable uncer- tainties. The first verification step allowed us to confirm the modelled processes and the benefits of our parameter estimation method. The second one confirmed the ability of the model to describe microcosm functioning under different abiotic conditions. This innovative combination of mechanistic modelling and model-guided experiments revealed successful to understand the algae-daphnid microcosm func- tioning. This approach appears promising and can be applied to various issues in the ecological and ecotoxicological fields.
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.ecolmodel.2015.09.020
- Accès au bibtex
-
-

- titre
- Methodology for Single-Cell Genetic Analysis of Planktonic Foraminifera for Studies of Protist Diversity and Evolution
- auteur
- Agnès K.M. Weiner, Raphael Morard, Manuel Weinkauf, Kate F. Darling, Aurore Andre, Frédéric Quillévéré, Yurika Ujiié, Christophe Jean Douady, Colomban de Vargas, Michal Kucera
- article
- Frontiers in Marine Science, 2016, 3 (255), pp.1-15. ⟨10.3389/fmars.2016.00255⟩
- resume
- Single-cell genetic analysis is an essential method to investigate the biodiversity and evolutionary ecology of marine protists. In protist groups that do not reproduce under laboratory conditions, this approach provides the only means to directly associate molecular sequences with cell morphology. The resulting unambiguous taxonomic identification of the DNA sequences is a prerequisite for barcoding and analyses of environmental metagenomic data. Extensive single-cell genetic studies have been carried out on planktonic foraminifera over the past 20 years to elucidate their phylogeny, cryptic diversity, biogeography, and the relationship between genetic and morphological variability. In the course of these investigations, it has become evident that genetic analysis at the individual specimen level is confronted by innumerable challenges ranging from the negligible amount of DNA present in the single cell to the substantial amount of DNA contamination introduced by endosymbionts or food particles. Consequently, a range of methods has been developed and applied throughout the years for the genetic analysis of planktonic foraminifera in order to enhance DNA amplification success rates. Yet, the description of these methods in the literature rarely occurred with equivalent levels of detail and the different approaches have never been compared in terms of their efficiency and reproducibility. Here, aiming at a standardization of methods, we provide a comprehensive review of all methods that have been employed for the single-cell genetic analysis of planktonic foraminifera. We compile data on success rates of DNA amplification and use these to evaluate the effects of key parameters associated with the methods of sample collection, storage and extraction of single-cell DNA. We show that the chosen methods influence the success rates of single-cell genetic studies, but the differences between them are not sufficient to hinder comparisons between studies carried out by different methods. The review thus not only provides a comprehensive reference with guidelines for future genetic studies on foraminifera, but it also establishes an important benchmark for investigations using existing single-cell datasets. The methods are widely applicable and the review may help to establish similar standard principles for their utilization in other protist groups.
- typdoc
- Journal articles
- DOI
- DOI : 10.3389/fmars.2016.00255
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- titre
- Sustainable development policies and the spread of land-sharing practices. A statistical assessment in a frontier region of the Brazilian Amazon
- auteur
- Xavier Arnauld de Sartre, Johan Oszwald, Iran Veiga, Monica Castro, William Assis, Fernando Michelloti, Carla Rocha, Haroldo Souza, Pascal Sebille, Sylvain Dolédec, Patrick Lavelle
- article
- Journal of Rural Studies, 2016, 48, pp.65 - 76. ⟨10.1016/j.jrurstud.2016.09.009⟩
- resume
- Agrarian reform has become at highly topical issue in Brazil and is proceeding mainly along the Amazonian pioneer fronts, thus jeopardising the continuity of forest cover. Although it is sometimes accompanied by highly proactive policies for sustainable development, the results of these policies are extremely variable. In this article, we compare four sites where agrarian reforms have been applied; they are located along the boundary between eastern Amazonia (deforestation arc) and central Amazonia (along a pioneer front) and are variously covered by sustainable development policies. In each of these sites, we surveyed plant cover, existing production systems, the characteristics of the local populations and their quality of life in the sites themselves. We bring out discrepancies between sustainable development policies applied in the sites and their environmental preservation status. These discrepancies cannot be accounted for by the characteristics of the populations and do not bear any relation to people's quality of life in the different sites. While effects of context and of local levels of acceptance account for the success or failure of sustainable development projects, the agrarian reform policies we investigated are characterized by impacts that are negative for the environment but positive for the quality of life of local populations. By proposing a series of multivariate analyses and their combination through a scalar analysis, this article also puts forward an original methodology for studies of relationships between people and their environment.
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- Journal articles
- DOI
- DOI : 10.1016/j.jrurstud.2016.09.009
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- titre
- Review: Impact of underground structures on the flow of urban groundwater
- auteur
- Guillaume Attard, Thierry Winiarski, Yvan Rossier, Laurent Eisenlohr
- article
- Hydrogeology Journal, 2016, 24, pp.5-19. ⟨10.1007/s10040-015-1317-3⟩
- resume
- Property economics favours the vertical develop- ment of cities but flow of groundwater can be affected by the use of underground space in them. This review article presents the state of the art regarding the impact of distur- bances caused by underground structures (tunnels, basements of buildings, deep foundations, etc.) on the groundwater flow in urban aquifers. The structures built in the underground levels of urban areas are presented and organised in terms of their impact on flow: obstacle to the flow or disturbance of the groundwater budget of the flow system. These two types of disturbance are described in relation to the structure area and the urban area. The work reviewed shows, on one hand, the individual impacts of different urban underground structures, and on the other, their cumulative impacts on flow, using real case studies. Lastly, the works are placed in perspective re- garding the integration of underground structures with the aim of operational management of an urban aquifer. The literature presents deterministic numerical modelling as a tool capable of contributing to this aim, in that it helps to quantify the effect of an underground infrastructure project on groundwater flow, which is crucial for decision-making processes. It can also be an operational decision-aid tool for choosing construction techniques or for formulating strategies to manage the water resource.
- typdoc
- Journal articles
- DOI
- DOI : 10.1007/s10040-015-1317-3
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- titre
- Influence of oxidative homeostasis on bacterial density and cost of infection in Drosophila–Wolbachia symbioses
- auteur
- David Monnin, Natacha Kremer, C. Berny, Hélène Henri, Adeline Dumet, Yann Voituron, Emmanuel Desouhant, Fabrice Vavre
- article
- Journal of Evolutionary Biology, 2016, 29, pp.1211-1222. ⟨10.1111/jeb.12863⟩
- resume
- The evolution of symbioses along the continuum between parasitism and mutualism can be influenced by the oxidative homeostasis, that is the bal- ance between reactive oxygen species (ROS) and antioxidant molecules. Indeed, ROS can contribute to the host immune defence to regulate sym- biont populations, but are also toxic. This interplay between ROS and sym- biosis is notably exemplified by recent results in arthropod–Wolbachia interactions. Wolbachia are symbiotic bacteria involved in a wide range of interactions with their arthropods hosts, from facultative, parasitic associa- tions to obligatory, mutualistic ones. In this study, we used Drosophila–Wol- bachia associations to determine whether the oxidative homeostasis plays a role in explaining the differences between phenotypically distinct arthro- pod–Wolbachia symbioses. We used Drosophila lines with different Wolbachia infections and measured the effects of pro-oxidant (paraquat) and antioxi- dant (glutathione) treatments on the Wolbachia density and the host sur- vival. We show that experimental manipulations of the oxidative homeostasis can reduce the cost of the infection through its effect on Wol- bachia density. We discuss the implication of this result from an evolution- ary perspective and argue that the oxidative homeostasis could underlie the evolution of tolerance and dependence on Wolbachia.
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- Journal articles
- DOI
- DOI : 10.1111/jeb.12863
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- titre
- Colonic fermentation promotes decompression sickness in Rats.
- auteur
- Sébastien de Maistre, Nicolas Vallée, Emmanuel Gempp, Kate Lambrechts, Pierre Louge, Claude Duchamp, Jean-Eric Blatteau
- article
- Scientific Reports, 2016, 6 (20379), pp.1-7. ⟨10.1038/srep20379⟩
- resume
- Massive bubble formation after diving can lead to decompression sickness (DCS). During dives with hydrogen as a diluent for oxygen, decreasing the body’s H2 burden by inoculating hydrogen-metabolizing microbes into the gut reduces the risk of DCS. So we set out to investigate if colonic fermentation leading to endogenous hydrogen production promotes DCS in fasting rats. Four hours before an experimental dive, 93 fasting rats were force-fed, half of them with mannitol and the other half with water. Exhaled hydrogen was measured before and after force-feeding. Following the hyperbaric exposure, we looked for signs of DCS. A higher incidence of DCS was found in rats force-fed with mannitol than in those force-fed with water (80%, [95%CI 56, 94] versus 40%, [95%CI 19, 64], p < 0.01). In rats force-fed with mannitol, metronidazole pretreatment reduced the incidence of DCS (33%, [95%CI 15, 57], p = 0.005) at the same time as it inhibited colonic fermentation (14 ± 35 ppm versus 118 ± 90 ppm, p = 0.0001). Pre-diveingestion of mannitol increased the incidence of DCS in fasting rats when colonic fermentation peaked during the decompression phase. More generally, colonic fermentation in rats on a normal diet could promote DCS through endogenous hydrogen production.
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- DOI
- DOI : 10.1038/srep20379
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- titre
- No Evidence That Nitrogen Limitation Influences the Elemental Composition of Isopod Transcriptomes and Proteomes
- auteur
- Clémentine François, L. Duret, Laurent Simon, Florian Mermillod-Blondin, Florian Malard, Lara Konecny-Dupré, Rémi Planel, Simon Penel, Christophe Jean Douady, Tristan Lefébure
- article
- Molecular Biology and Evolution, 2016, 33 (10), pp.2605-2620. ⟨10.1093/molbev/msw131⟩
- resume
- The field of stoichiogenomics aims at understanding the influence of nutrient limitations on the elemental composition of the genome, transcriptome, and proteome. The 20 amino acids and the 4 nt differ in the number of nutrients they contain, such as nitrogen (N). Thus, N limitation shall theoretically select for changes in the composition of proteins or RNAs through preferential use of N-poor amino acids or nucleotides, which will decrease the N-budget of an organism. While these N-saving mechanisms have been evidenced in microorganisms, they remain controversial in multicellular eukaryotes. In this study, we used 13 surface and subterranean isopod species pairs that face strongly contrasted N limitations, either in terms of quantity or quality. We combined in situ nutrient quantification and transcriptome sequencing to test if N limitation selected for N-savings through changes in the expression and composition of the transcriptome and proteome. No evidence of N-savings was found in the total N-budget of transcriptomes or proteomes or in the average protein N-cost. Nevertheless, subterranean species evolving in N-depleted habitats displayed lower N- usage at their third codon positions. To test if this convergent compositional change was driven by natural selection, we developed a method to detect the strand-asymmetric signature that stoichiogenomic selection should leave in the substitution pattern. No such signature was evidenced, indicating that the observed stoichiogenomic-like patterns were attributable to nonadaptive processes. The absence of stoichiogenomic signal despite strong N limitation within a powerful phylogenetic framework casts doubt on the existence of stoichiogenomic mechanisms in metazoans.
- typdoc
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- DOI
- DOI : 10.1093/molbev/msw131
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- titre
- Identification of B-type procyanidins in Fallopia spp. involved in biological denitrification inhibition
- auteur
- Clément Bardon, Florence Piola, Feth El Zahar Haichar, Guillaume Meiffren, Gilles Comte, Boris Missery, Manon Balby, Poly Franck
- article
- Environmental Microbiology, 2016, 18 (2), pp.644-655. ⟨10.1111/1462-2920.13062⟩
- resume
- Nitrogen (N) is considered as a main limiting factor in plant growth, and nitrogen losses through denitrification can be responsible for severe decreases in plant productivity. Recently, it was dem- onstrated that Fallopia spp. is responsible for biologi- cal denitrification inhibition (BDI) through the release of unknown secondary metabolites. Here, we investi- gate the secondary metabolites involved in the BDI of Fallopia spp. The antioxidant, protein precipitation capability of Fallopia spp. extracts was measured in relation to the aerobic respiration and denitrification of two bacteria (Gram positive and Gram negative). Proanthocyanidin concentrations were estimated. Proanthocyanidins in extracts were characterized by chromatographic analysis, purified and tested on the bacterial denitrification and aerobic respiration of two bacterial strains. The effect of commercial procyanidins on denitrification was tested on two different soil types. Denitrification and aerobic respiration inhibition were correlated with protein precipitationcapacityandconcentrationof proanthocyanidins but not to antioxidant capacity. These proanthocyanidins were B-type procyanidins that inhibited denitrification more than the aerobic respiration of bacteria. In addition, procyanidins also inhibited soil microbial denitrification. We demon- strate that procyanidins are involved in the BDI of Fallopia spp. Our results pave the way to a better understanding of plant–microbe interactions and highlight future applications for a more sustainable agriculture.
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- Journal articles
- DOI
- DOI : 10.1111/1462-2920.13062
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- titre
- Effects of contrasting wave conditions on scour and drag on pioneer tidal marsh plants
- auteur
- Alexandra Silinski, Maike Heuner, Peter Troch, Sara Puijalon, Tjeerd J. Bouma, J. Schoelynck, Uwe Schröder, Elmar Fuchs, Patrick Meire, Stijn Temmerman
- article
- Geomorphology, 2016, 255, pp.49-62. ⟨10.1016/j.geomorph.2015.11.021⟩
- resume
- Tidal marshes are increasingly valued for protecting shorelines against wave impact, but waves in turn may limit the initial establishment of tidal marsh pioneer plants. In estuaries, the shorelines typically experience a wide range of wave periods, varying from short period wind waves (usually of around 1–2 s in fair weather conditions) to long ship-generated waves, with secondary waves in the order of 2–7 s and primary waves with periods that can exceed 1 min. Waves are known to create sediment scour around, as well as to exert drag forces on obstacles such as seedlings and adults of establishing pioneer plant species. In intertidal systems, these two mechanisms have been identified as main causes for limiting potential colonization of bare tidal flats. In this paper, we want to assess to which extent common quantitative formulae for predicting local scour and drag forces on rigid cylindrical obstacles are valid for the estimation of scour and drag on slightly flexible plants with contrasting morphology, and hence applicable to predict plant establishment and survival under contrasting wave condi- tions. This has been tested in a full-scale wave flume experiment on two pioneer species (Scirpus maritimus and Scirpus tabernaemontani) and two life stages (seedlings and adults of S. maritimus) as well as on cylindrical reference sticks, which we have put under a range of wave periods (2–10 s), intended to mimic natural wind waves (short period waves) and ship-induced waves (artificial long period waves), at three water levels (5, 20, 35 cm). Our findings suggest that at very shallow water depths (5 cm) particular hydrodynamic conditions are created that lead to drag and scour that deviate from predictions. For higher water levels (20, 35 cm) scour can be well predicted for all wave conditions by an established formula for wave-induced scour around rigid cyl- inders. Drag forces can be relatively well predicted after introducing experimentally derived drag coefficients that are specific for the different plant morphologies. Best predictions were found for plants with a simple near- cylindrical morphology such as S. tabernaemontani, but are less accurate for plants of more complex structure such as S. maritimus, particularly for long period waves. In conclusion, our study offers valuable insights towards predicting/modelling the conditions under which seedlings and shoots of pioneer species can establish, and elu- cidates that long waves are more likely to counteract successful plant establishment than natural short waves.
- typdoc
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- DOI
- DOI : 10.1016/j.geomorph.2015.11.021
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- titre
- Novel energy-saving strategies to multiple stressors in birds: the ultradian regulation of body temperature
- auteur
- Glen J. Tattersall, Damien Roussel, Yann Voituron, Loïc Teulier
- article
- Proceedings of the Royal Society B: Biological Sciences, 2016, 283 (20161551), pp.1-7. ⟨10.6084/m9.fig-share.c.3464604⟩
- resume
- This study aimed to examine thermoregulatory responses in birds facing two commonly experienced stressors, cold and fasting. Logging devices allowing long-term and precise access to internal body temperature were placed within the gizzards of ducklings acclimated to cold (CA) (58C) or thermo- neutrality (TN) (258C). The animals were then examined under three equal 4-day periods: ad libitum feeding, fasting and re-feeding. Through the analysis of daily as well as short-term, or ultradian, variations of body temp- erature, we showed that while ducklings at TN show only a modest decline in daily thermoregulatory parameters when fasted, they exhibit reduced surface temperatures from key sites of vascular heat exchange during fasting. The CA birds, on the other hand, significantly reduced their short-term vari- ations of body temperature while increasing long-term variability when fasting. This phenomenon would allow the CA birds to reduce the energe- tic cost of body temperature maintenance under fasting. By analysing ultradian regulation of body temperature, we describe a means by which an endotherm appears to lower thermoregulatory costs in response to the combined stressors of cold and fasting.
- typdoc
- Journal articles
- DOI
- DOI : 10.6084/m9.fig-share.c.3464604
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- titre
- Nomenclature for the Nameless: A Proposal for an Integrative Molecular Taxonomy of Cryptic Diversity Exemplified by Planktonic Foraminifera
- auteur
- Raphael Morard, Gilles Escarguel, Agnès K.M. Weiner, Aurore Andre, Christophe Jean Douady, Christopher M. Wade, Kate F. Darling, Yurika Ujiié, Heidi A. Seears, Frédéric Quillévéré, Thibault Garidel-Thoron, Colomban de Vargas, Michal Kucera
- article
- Systematic Biology, 2016, 65 (5), pp.925-940. ⟨10.1093/sysbio/syw031⟩
- resume
- Investigations of biodiversity, biogeography, and ecological processes rely on the identification of “species” as biologically significant, natural units of evolution. In this context, morphotaxonomy only provides an adequate level of resolution if reproductive isolation matches morphological divergence. In many groups of organisms, morphologically defined species often disguise considerable genetic diversity, which may be indicative of the existence of cryptic species. The diversity hidden by morphological species can be disentangled through genetic surveys, which also provide access to data on the ecological distribution of genetically circumscribed units. These units can be identified by unique DNA sequence motifs and allow studies of evolutionary and ecological processes at different levels of divergence. However, the nomenclature of genetically circumscribed units within morphological species is not regulated and lacks stability. This represents a major obstacle to efforts to synthesize and communicate data on genetic diversity for multiple stakeholders. We have been confronted with such an obstacle in our work on planktonic foraminifera, where the stakeholder community is particularly diverse, involving geochemists, paleoceanographers, paleontologists, and biologists, and the lack of stable nomenclature beyond the level of formal morphospecies prevents effective transfer of knowledge. To circumvent this problem, we have designed a stable, reproducible, and flexible nomenclature system for genetically circumscribed units, analogous to the principles of a formal nomenclature system. Our system is based on the definition of unique DNA sequence motifs collocated within an individual, their typification (in analogy with holotypes), utilization of their hierarchical phylogenetic structure to define levels of divergence below that of the morphospecies, and a set of nomenclature rules assuring stability. The resulting molecular operational taxonomic units remain outside the domain of current nomenclature codes, but are linked to formal morphospecies as regulated by the codes. Subsequently, we show how this system can be applied to classify genetically defined units using the SSU rDNA marker in planktonic foraminifera and we highlight its potential use for other groups of organisms where similarly high levels of connectivity between molecular and formal taxonomies can be achieved. [Cryptic species; genetic diversity; planktonic foraminifera; molecular nomenclature; MOTUs.]
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- DOI : 10.1093/sysbio/syw031
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- titre
- The impact of severe drought on survival, fecundity, and population persistence in an endangered amphibian.
- auteur
- Hugo Cayuela, Dragan Arsovski, E. Bonnaire, R. Duguet, Pierre Joly, Aurélien Besnard
- article
- Ecosphere, 2016, 7 (2 - e01246), pp.1-12. ⟨10.1002/ecs2.1246⟩
- resume
- Climate is globally changing. In Europe, studies have highlighted an increasing trend in both the frequency and magnitude of droughts. Abrupt changes in the frequency, location, or intensity of extreme heatwaves and droughts can have direct and severe effects on wild populations. Amphibians are the planet's most threatened group of vertebrates, with over 40% of known species considered in decline. To date, researchers have mainly focused on the influence of repeated droughts on species occurrence and community composition; however, evidence of the direct impact of climatic factors on the demographic parameters of amphibians is currently not well documented. Further investigation of this issue is therefore of critical importance in order to optimize local and global wildlife conservation policies in the context of a changing climate. This study used capture-recapture data to investigate the impact of severe drought on the survival and fecundity of a threatened amphibian, the yellow-bellied toad (Bombina variegata, L.), as well as to predict how potential changes in the frequency of droughts might influence the population growth rate. By developing multievent capture-recapture models, we showed that severe drought has a negative impact on fecundity and postmetamorphic survival at different ontogenetic stages. Then, using stochastic matrix population models, we predicted that changes in drought frequency negatively influence the population growth rate, which is a warning sign for population persistence. Direct conservation actions are then proposed to mitigate the detrimental effects of drought on population dynamics.
- typdoc
- Journal articles
- DOI
- DOI : 10.1002/ecs2.1246
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- titre
- Caractérisation des boues de vidange dépotées sur les lits de séchage de zagtouli (Ouagadougou)
- auteur
- Martine Kone, Emmanuelle Service, Yacouba Ouattara, Paul Ouattara, Lucien Bonou, Pierre Joly
- article
- International Journal of Biological and Chemical Sciences, 2016, 10 (6), ⟨10.4314/ijbcs.v10i6.30⟩
- resume
- A Ouagadougou comme dans la plupart des grandes villes africaines, il y a très peu de réseau d’égout. Les ouvrages d’assainissement autonome sont les plus couramment utilisés. Ces ouvrages produisent des boues qu’il faut vidanger et traiter adéquatement afin de préserver la santé des populations et protéger l’environnement. En effet, les risques sont réels, eu égard à l’utilisation des boues de vidange fraiches dans l’agriculture, en plus des dangers potentiels de leurs rejet à l’état brut dans la nature. A cet effet, le traitement par déshydratation constitue une solution. Les boues dépotées à la station de traitement par lits de séchage de Zagtouli (Ouagadougou) sont essentiellement issues des fosses septiques et des fosses toutes eaux. L’objectif du présent travail est de mettre en exergue les caractéristiques de ces boues pour guider le choix de technologies alternatives de traitement. A cet effet, les paramètres physico-chimiques et bactériologiques ont été mesurés selon les normes françaises. Les principaux résultats indiquent que la Demande Chimique en Oxygène (DCO) et la Demande Biochimique en Oxygène (DBO5) de ces boues fluides, présentent des valeurs moyennes respectives de 1950 mg O2/let 785 mg O2/l. Quant aux nutriments, ces boues se sont révélées particulièrement riches en azote ammoniacal avec une teneur moyenne de 557 mg/l, tandis que les nitrates et orthophosphates ont des concentrations moyennes de 24 et 39 mg/l respectivement.
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- DOI
- DOI : 10.4314/ijbcs.v10i6.30
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- titre
- Deterministic modelling of the cumulative impacts of underground structures on urban groundwater flow and the definition of a potential state of urban groundwater flow: example of Lyon, France
- auteur
- Guillaume Attard, Yvan Rossier, Thierry Winiarski, Loann Cuvillier, Laurent Eisenlohr
- article
- Hydrogeology Journal, 2016, 24, pp.1213-1229. ⟨10.1007/s10040-016-1385-z⟩
- resume
- Underground structures have been shown to have a great influence on subsoil resources in urban aquifers. A methodology to assess the actual and the potential state of the groundwater flow in an urban area is proposed. The study develops a three-dimensional modeling approach to understand the cumulative impacts of underground infrastructures on urban groundwater flow, using a case in the city of Lyon (France). All known underground structures were integrated in the numerical model. Several simulations were run: the actual state of groundwater flow, the potential state of ground- water flow (without underground structures), an intermediate state (without impervious structures), and a transient simulation of the actual state of groundwater flow. The results show that underground structures fragment groundwater flow systems leading to a modification of the aquifer regime. For the case studied, the flow systems are shown to be stable over time with a transient simulation. Structures with drainage sys- tems are shown to have a major impact on flow systems. The barrier effect of impervious structures was negligible because of the small hydraulic gradient of the area. The study demon- strates that the definition of a potential urban groundwater flow and the depiction of urban flow systems, which involves understanding the impact of underground structures, are im- portant issues with respect to urban underground planning.
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- Journal articles
- DOI
- DOI : 10.1007/s10040-016-1385-z
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- titre
- Mobbing behaviour varies according to predator dangerousness and occurrence
- auteur
- Mylène Dutour, Jean-Paul Léna, Thierry Lengagne
- article
- Animal Behaviour, 2016, 119, pp.119-124. ⟨10.1016/j.anbehav.2016.06.024⟩
- resume
- Animals possess various antipredator behaviours to reduce their risk of predation. Whereas most prey make considerable effort to avoid their predators, sometimes individuals approach and mob predators as a group. Among the types of predators that elicit mobbing, raptors such as hawks and owls are one of the more consistent targets. We conducted playback experiments to investigate the strength of mobbing behaviour according to the perceived risk associated with either predator dangerousness or local pre- dation pressure. We ␣rst determined whether mobbing is speci␣c to dangerous predators or more broadly directed at predatory species. We experimentally investigated whether prey can discriminate the level of dangerousness of two owl species. Our results indicate that prey adjusted the strength of their mobbing behaviour according to the perceived risk: passerine birds mobbed the Eurasian pygmy owl, Glaucidium passerinum (i.e. a dangerous predator) but not the boreal owl, Aegolius funereus (i.e. a far less dangerous species). Second, we compared mobbing behaviour in similar habitats differing in predation pressure (with or without pygmy owls). Working on identical bird communities, we revealed that mobbing varied in relation to the local presence of the predator. Where the pygmy owl was absent, calls of this dangerous predator failed to elicit mobbing among passerine birds although they responded strongly to a playback of a mobbing chorus. This study provides experimental evidence that intense predation increases the expression of cooperative mobbing in passerine birds.
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- Journal articles
- DOI
- DOI : 10.1016/j.anbehav.2016.06.024
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- titre
- Insights into the leaf cuticle fine structure of Ginkgoites skottsbergii Lundblad from the Albian of Patagonia and its relationship within Ginkgoaceae
- auteur
- Gaëtan Guignard, Georgina M del Fueyo, Liliana Villar de Seoane, Martin Carrizo, Maiten A. Lafuente Diaz
- article
- Review of Palaeobotany and Palynology, 2016, 232, pp.22-39. ⟨10.1016/j.revpalbo.2016.05.002⟩
- resume
- New specimens of Ginkgoites skottsbergii Lundblad collected from the Albian Kachaike Formation at the type locality in Santa Cruz Province, Argentina are characterized with additional scanning and transmission electron microscopic observations and EDS elemental analysis. The micromorphology of the amphistomatic and 12-segmented leaf of G. skottsbergii shows a smooth lamina with straight and pitted anticlinal and slightly granulate periclinal walls, abundant epicuticular wax on the petiole surface, and monocyclic to partially dicyclic stomatal apparatuses with between six and eight papillate to non-papillate, finely striated subsidiary cells and guard cells with smooth walls. Palaeoenvironmental considerations suggest that G. skottsbergii was a mesophytic plant. The TEM studies of ordinary epidermal cell cuticles and subsidiary and guard cell cuticles reveal the general ultrastructural features of Ginkgoaceae. Using confidence intervals based on 30 statistical measurements and the Mann–Whitney test for five measurements of EDS ratios of the elements, 33 ultrastructural characters were identified that enabled discussion at different taxonomic levels. Comparisons with the previously studied Ginkgoites ticoensis Archangelsky reveal that 14 of these characteristics could be species features that reinforce the identity of G. skottsbergii, and 19 could be genus features. EDS analysis and comparisons with G. ticoensis yielded five ratios using Cl, N, K, S, and Ca, revealing seven ratios of potential species interest and eight ratios at the genus level among the three zones evaluated in the leaf cuticle of each species. A three-dimensional reconstruction of the cuticle and an ultrastructural identification key for each of the three types of cuticle are also provided, i.e., from the ordinary epidermal cell and the subsidiary and guard cells of the stomatal apparatus. Fruitful statistical comparisons with two previously studied ginkgos allow discussion of the relationships within the Ginkgoaceae with respect to 18 features, six of them being potentially significant at the genus level and four at the family level.
- typdoc
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- DOI
- DOI : 10.1016/j.revpalbo.2016.05.002
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- titre
- Proline as a fuel for insect flight: enhancing carbohydrate oxidation in hymenopterans
- auteur
- Loïc Teulier, Jean-Michel Weber, Julie Crevier, Charles-A. Darveau
- article
- Proceedings of the Royal Society B: Biological Sciences, 2016, 283: 20160333, pp.1-8. ⟨10.1098/rspb.2016.0333⟩
- resume
- Bees are thought to be strict users of carbohydrates as metabolic fuel for flight. Many insects, however, have the ability to oxidize the amino acid proline at a high rate, which is a unique feature of this group of animals. The presence of proline in the haemolymph of bees and in the nectar of plants led to the hypothesis that plants may produce proline as a metabolic reward for pollina- tors. We investigated flight muscle metabolism of hymenopteran species using high-resolution respirometry performed on permeabilized muscle fibres. The muscle fibres of the honeybee, Apis mellifera, do not have a detectable capacity to oxidize proline, as those from the migratory locust, Locusta migratoria, used here as an outgroup representative. The closely related bumblebee, Bombus impatiens, can oxidize proline alone and more than doubles its respiratory capacity when proline is combined with carbohydrate-derived substrates. A distant wasp species, Vespula vulgaris, exhibits the same metabolic pheno- type as the bumblebee, suggesting that proline oxidation is common in hymenopterans. Using a combination of mitochondrial substrates and inhibi- tors, we further show that in B. impatiens, proline oxidation provides reducing equivalents and electrons directly to the electron transport system. Together, these findings demonstrate that some bee and wasp species can greatly enhance the oxidation of carbohydrates using proline as fuel for flight.
- typdoc
- Journal articles
- DOI
- DOI : 10.1098/rspb.2016.0333
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- titre
- Life-history strategies constrain invertebrate community tolerance to multiple stressors: A case study in the Ebro basin
- auteur
- Cédric P. Mondy, Isabel Munoz, Sylvain Dolédec
- article
- Science of the Total Environment, 2016, 572, pp.196-206. ⟨10.1016/j.scitotenv.2016.07.227⟩
- resume
- Context: Multiple stressors constitute a serious threat to aquatic ecosystems, particularly in the Mediterranean region where water scarcity is likely to interact with other anthropogenic stressors. Biological traits potentially allow the unravelling of the effects of multiple stressors. However, thus far, trait-based approaches have failed to fully deliver on their promise and still lack strong predictive power when multiple stressors are present. Goal: We aimed to quantify specific community tolerances against six anthropogenic stressors and investigate the responses of the underlying macroinvertebrate biological traits and their combinations. Methods: We built and calibrated boosted regression tree models to predict community tolerances using multiple biological traits with a priori hypotheses regarding their individual responses to specific stressors. We analysed the combinations of traits underlying community tolerance and the effect of trait association on this tolerance. Results: Our results validated the following three hypotheses: (i) the community tolerance models efficiently and robustly related trait combinations to stressor intensities and, to a lesser extent, to stressors related to the presence of dams and insecticides; (ii) the effects of traits on community tolerance not only depended on trait identity but also on the trait associations emerging at the community level from the co-occurrence of different traits in species; and (iii) the community tolerances and the underlying trait combinations were speci␣c to the different stressors. Conclusion: This study takes a further step towards predictive tools in community ecology that consider
- typdoc
- Journal articles
- DOI
- DOI : 10.1016/j.scitotenv.2016.07.227
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- titre
- Ancient split of major genetic lineages of European Black Pine: evidence from chloroplast DNA
- auteur
- Krassimir D. Naydenov, Michel K. Naydenov, Alexandrov Alexander, Kole Vasilevski, Veselka Gyuleva, Vlado Metevski, Biljana Nikolic, Venceslas Goudiaby, Faruk Bogunic, Despina Paitaridou, Andréas Christou, Irina Goia, Christopher Carcaillet, Adrian Escudero Alcantara, Cengiz Ture, Suleyman Gulcu, Lorenzo Peruzzi, Salim Kamary, Srdjan Bojovic, Georgi Hinkov, Anatoly Tsarev
- article
- Tree Genetics and Genomes, 2016, 12 (68), pp.1-18. ⟨10.1007/s11295-016-1022-y⟩
- resume
- The European Black Pine (Pinus nigra Arn.) has a long and complex history. Genetic distance and frequency analyses identified three differentiated genetic groups, which corresponded to three wide geographical areas: Westerns Mediterranean, Balkan Peninsula and Asia Minor. These groups shared common ancestors (14.75 and 10.72 Ma). The most recent splits occurred after the Messinian Salinity Crisis (4.37 Ma) and the Early–Middle Pleistocene Transitions (0.93 Ma). The posterior ancestral population size (Na) is 260, 000–265,000 individuals. Each pool is further fragmented, with evidence of a phylogeographic structure (Nst > Gst) typ- ically observed in some natural populations from the Western Mediterranean region and the Balkan Peninsula. The labora- tory analysis was performed by fragment analysis—i.e. elec- trophoretic sizing of polymerase chain reaction fragments, combined with the sequencing analysis of 33 % of all individ- uals as a control. Intense sampling of chloroplast DNA poly- morphisms (3154 individuals and 13 markers: SNPs and SSRs) over the full area of the species’ natural distribution indicated moderate among-population variability (Gst(nc) ≤ 0.177) in various parts of its range. These results indicate that the natural populations have long migration his- tories that differ from one another and that they have been strongly phylogeographically affected by complex patterns of isolation, speciation and fragmentation. Long and varying climatic fluctuations in the region of the principal genetic group have been the probable cause of different forest com- munity associations with different successional patterns resulting in interglacial refugia vs. macro long-term refugia.
- typdoc
- Journal articles
- DOI
- DOI : 10.1007/s11295-016-1022-y
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- titre
- Demographic responses to weather fluctuations are context dependent in a long-lived amphibian
- auteur
- Hugo Cayuela, Dragan Arsovski, Jean-Marc Thirion, Eric Bonnaire, Julian Pichenot, Sylvain Boitaud, Claude Miaud, Pierre Joly, Aurélien Besnard
- article
- Global Change Biology, 2016, 22, pp.2676-2687. ⟨10.1111/gcb.13290⟩
- resume
- Weather fluctuations have been demonstrated to affect demographic traits in many species. In long-lived organisms, their impact on adult survival might be buffered by the evolution of traits that reduce variation in interannual adult survival. For example, skipping breeding is an effective behavioral mechanism that may limit yearly variation in adult survival when harsh weather conditions occur; however, this in turn would likely lead to strong variation in recruitment. Yet, only a few studies to date have examined the impact of weather variation on survival, recruitment and breeding probability simultaneously in different populations of the same species. To fill this gap, we studied the impact of spring temperatures and spring rainfall on survival, on reproductive skipping behavior and on recruitment in five populations of a long-lived amphibian, the yellow-bellied toad (Bombina variegata). Based on capture–recapture data, our findings demonstrate that survival depends on interactions between age, population and weather variation. Varying weather conditions in the spring result in strong variation in the survival of immature toads, whereas they have little effect on adult toads. Breeding probability depends on both the individual’s previous reproductive status and on the weather conditions during the current breeding season, leading to high interannual variation in recruit- ment. Crucially, we found that the impact of weather variation on demographic traits is largely context dependent and may thus differ sharply between populations. Our results suggest that studies predicting the impact of climate change on population dynamics should be taken with caution when the relationship between climate and demo- graphic traits is established using only one population or few populations. We therefore highly recommend further research that includes surveys replicated in a substantial number of populations to account for context-dependent variation in demographic processes.
- typdoc
- Journal articles
- DOI
- DOI : 10.1111/gcb.13290
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- titre
- Characterization of Macroinvertebrate Communities in the Hyporheic Zone of River Ecosystems Reflects the Pump-Sampling Technique Used
- auteur
- Rachel Stubbington, Marie-José Dole-Olivier, Diana M.P. Galassi, John-Paul Hogan, Paul-J. Wood
- article
- PLoS ONE, 2016, 11 (10: e0164372.), pp.1-27. ⟨10.1371/journal.pone.0164372⟩
- resume
- The hyporheic zone of river ecosystems provides a habitat for a diverse macroinvertebrate community that makes a vital contribution to ecosystem functioning and biodiversity. How- ever, effective methods for sampling this community have proved difficult to establish, due to the inaccessibility of subsurface sediments. The aim of this study was to compare the two most common semi-quantitative macroinvertebrate pump-sampling techniques: Bou- Rouch and vacuum-pump sampling. We used both techniques to collect replicate samples in three contrasting temperate-zone streams, in each of two biogeographical regions (Atlantic region, central England, UK; Continental region, southeast France). Results were typically consistent across streams in both regions: Bou-Rouch samples provided signifi- cantly higher estimates of taxa richness, macroinvertebrate abundance, and the abun- dance of all UK and eight of 10 French common taxa. Seven and nine taxa which were rare in Bou-Rouch samples were absent from vacuum-pump samples in the UK and France, respectively; no taxon was repeatedly sampled exclusively by the vacuum pump. Rarefac- tion curves (rescaled to the number of incidences) and non-parametric richness estimators indicated no significant difference in richness between techniques, highlighting the capture of more individuals as crucial to Bou-Rouch sampling performance. Compared to assem- blages in replicate vacuum-pump samples, multivariate analyses indicated greater distinc- tion among Bou-Rouch assemblages from different streams, as well as significantly greater consistency in assemblage composition among replicate Bou-Rouch samples collected in one stream. We recommend Bou-Rouch sampling for most study types, including rapid bio- monitoring surveys and studies requiring acquisition of comprehensive taxon lists that include rare taxa. Despite collecting fewer macroinvertebrates, vacuum-pump sampling remains an important option for inexpensive and rapid sample collection.
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- Journal articles
- DOI
- DOI : 10.1371/journal.pone.0164372
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- titre
- A Jurassic wood providing insights into the earliest step in Ginkgo wood evolution
- auteur
- Zikun Jiang, Yongdong Wang, Marc Philippe, Wu Zhang, Ning Tian, Shaolin Zheng
- article
- Scientific Reports, 2016, 6 (38191), pp.1-8. ⟨10.1038/srep38191⟩
- resume
- The fossil record of Ginkgo leaf and reproductive organs has been well dated to the Mid-Jurassic (170 Myr). However, the fossil wood record that can safely be assigned to Ginkgoales has not yet been reported from strata predating the late Early Cretaceous (ca. 100 Myr). Here, we report a new fossil wood from the Mid-Late Jurassic transition deposit (153–165 Myr) of northeastern China. The new fossil wood specimen displays several Ginkgo features, including inflated axial parenchyma and intrusive tracheid tips. Because it is only slightly younger than the oldest recorded Ginkgo reproductive organs (the Yima Formation, 170 Myr), this fossil wood very probably represents the oldest bona fide fossil Ginkgo wood and the missing ancestral form of Ginkgo wood evolution.
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- DOI
- DOI : 10.1038/srep38191
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- titre
- Tree cover and seasonal precipitation drive understorey flammability in alpine mountain forests
- auteur
- Thibaut Fréjaville, Thomas Curt, Christopher Carcaillet
- article
- Journal of Biogeography, 2016, 43 (9), pp.1869-1880. ⟨10.1111/jbi.12745⟩
- resume
- Aim Little is known about the understorey flammability of European moun- tain forests. The aim of this study was to determine the relative effects of cli- mate, vegetation structure and composition on the fuel-driven variation in fire spread and intensity. Location The western Alps. Methods Fire spread and intensity were simulated under constant moisture and weather conditions for a wide range of understorey fuel parameters mea- sured in the litter, grass and shrub layers. Simulation outputs were used to compare understorey flammability between different forest ecosystem types (FET). The FETs were characterized by using a co-inertia analysis between composition and the environment (vegetation structure and climate). The rela- tionships between these factors, fuel properties and understorey flammability were then tested using partial regression analyses. Results The most flammable forests displayed an open canopy (dry-subalpine and open-mediterranean) and grew in areas with dry autumns and wet and cold springs. Fire spread and intensity were controlled by the trade-off between tree cover and dead (litter) and live (grass and shrub) biomass load. Fire inten- sity also increased as a result of seasonal precipitation patterns (differential dis- tribution between the seasons): rainy springs enhanced biomass growth, whereas dry climates, especially in autumn, promoted shrub biomass and stim- ulated litter accumulation and residence (higher litterfall and lower decomposi- tion rates). Interestingly, we found a positive relationship between fire intensity and the proportion of conifers that disappeared after accounting for tree cover, indicating that, in the Alps, the open canopy structure of needle-leaved forests makes them potentially more flammable than broad-leaved forests because of the higher load and continuity of surface fuels. Main conclusions Inter-relationships between tree cover, precipitation sea- sonality and species composition govern the understorey flammability of mountain forests. We also found evidence that tree cover strongly constrains fire spread by driving the amount and type of surface fuel, which suggests that land use change can have a strong influence on flammability patterns.
- typdoc
- Journal articles
- DOI
- DOI : 10.1111/jbi.12745
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- titre
- Subalpine fires: the roles of vegetation, climate and, ultimately, land uses.
- auteur
- Berangere Leys, Christopher Carcaillet
- article
- Climatic Change, 2016, 135, pp.683-697. ⟨10.1007/s10584-016-1594-4⟩
- resume
- Forest fires are controlled by local (vegetation, aspect, elevation, land uses) and regional (climate) factors. The role of these factors remains poorly assessed on centennial to millennial time scales. Here, we investigate fire and vegetation history in five subalpine sites over the past 8000 years to determine when, how, and why there were differences in fire regimes. We focus on time and aspect separately and account for vegetation composition. There are no significant differences in the fire return intervals among sites (~290 years between two fires). The rise of fire frequency from its lowest values (1.5 fires.1000 yr−1) at 8000–7000 years before present (yrBP) to its highest at 4000-3000 yrBP (5 fires-1000 yr−1) is well explained by the high temperatures and low precipitation of the Holocene, both leading to better conditions for fire ignition and spread. From 8000 yrBP, climate is likely the main factor driving the fire frequency on the north-facing sites, which contained mixed Larix decidua-Pinus cembra vegetation; whereas south-facing sites, dominated by the flammable P. cembra and broadleaved trees, appear to be driven by local features, including land use. A shift in the main drivers occurs at 4000 yrBP, when local processes start to control burning activity at all sites. Forest clearance for land use might have directly increased fire frequency, but has also helped to suppress fires through fuel limitation. During the last four millennia, land use likely altered the natural climate-vegetation-fire system mainly by converting forests to grassland by pastoral practices, thus leading to less fire and making the fire-vegetation-climate relationships more complex.
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- Journal articles
- DOI
- DOI : 10.1007/s10584-016-1594-4
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- titre
- Assessment of artificial substrates for evaluating groundwater microbial quality
- auteur
- Jérémy Voisin, Benoit Cournoyer, Florian Mermillod-Blondin
- article
- Ecological Indicators, 2016, 71, pp.577-586. ⟨10.1016/j.ecolind.2016.07.035⟩
- resume
- Protection of groundwater resources requires the development of reliable ecological indicators. Microor- ganisms involved in ecological services or being associated with particular hosts or habitats could be used for this purpose. Nevertheless, their tracking remains limited because of sampling issues, and a lack of devices for their long term monitoring. In the present study, three artificial substrates (glass and clay beads, and gravel particles) were tested in terms of efficacy at favoring bacterial growth, and at captur- ing bacterial diversity of waters (i.e., groundwater, surface water and wastewater). Total proteins, total carbohydrates, dehydrogenase and hydrolytic activities were used to monitor biofilm development on these artificial substrates. Fingerprinting analyses based on rrs (16S rRNA) − rrl (23S rRNA) spacer anal- yses (ARISA) and next generation sequencing (NGS) of partial rrs DNA segments (V5-V6) were used to compare operating taxonomic units (OTUs), and infer bacterial genera trapped on these substrates. Glass beads were found less efficient than the other two artificial substrates at increasing protein contents and microbial activities (hydrolytic and dehydrogenase activities). ARISA showed a discrimination of bacterial communities developing on artificial substrates that was matching water types. An incubation period of 7 days allowed a reliable assessment of bacterial diversity. From this incubation period, around 75% of water genera with more than four V5-V6 rrs DNA sequences detected in a water type were recovered from biofilms growing on artificial substrates. Based on relative abundances of genera, clay beads and gravel particles were more efficient than glass beads to capture and obtain bacterial communities match- ing those of the initial waters. Between 45–67% of similarities were found for these artificial substrates while it was between 36 and 43% for glass beads. This study demonstrated clay beads and gravel particles as being efficient tools for capturing bacterial diversity and monitoring bacterial growth. Overall, clay beads appeared the best choice for field monitoring because of the ease of their size standardization in comparison with gravel particles.
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- Journal articles
- DOI
- DOI : 10.1016/j.ecolind.2016.07.035
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- titre
- Measuring difference in edge avoidance in grassland birds: the Corncrake is less sensitive to hedgerow proximity than passerines
- auteur
- Jean Secondi, Aurélien G. Besnard, Yoan Fourcade
- article
- Journal of Ornithology, 2016, 157 (2), pp.515--523. ⟨10.1007/s10336-015-1281-7⟩
- resume
- Edge avoidance is an important feature of habitat selection in grassland birds, as their density is usually reduced close to habitat boundaries. In many extensively managed European grasslands, fragmentation is caused by the presence of wooded hedgerows dividing meadows. Comparing the magnitude of hedgerow avoidance by co-occurring species is essential for the management of grassland areas and the implementation of efficient conservation schemes. We quantified hedgerow avoidance by the Corncrake and four grassland passerines in western France. As expected, all species avoided hedgerows, but the effect was less pronounced for the Corncrake. We hypothesize that this may reflect a lower predation risk towards the larger and most inconspicuous species. Alternatively, social communication in Corncrakes may be less impeded by wooded vegetation than in passerines. However, the mechanisms responsible for the observed pattern remain uncertain. Nevertheless, our study provides a general technique that can be applied to measure boundary avoidance. This information is important for policymakers in their efforts to improve management guidelines, which often do not take edge effects into account.
- typdoc
- Journal articles
- DOI
- DOI : 10.1007/s10336-015-1281-7
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- titre
- Why roads and rivers can be straight or winding: how physical and sociohistorical factors produce contemporary regional landscape patterns
- auteur
- Bernhard Statzner, Nuria Bonada, Vincent H. Resh
- article
- Freshwater Science, 2016, 35 (4), pp.1-15. ⟨10.1086/688494⟩
- resume
- Efforts to understand and predict socioecological systems in an historical context have increased. We investigated sinuosity patterns of roads and rivers to understand why the geometric design of roads and rivers corresponds to natural physical constraints in some regions but not in others. We hypothesized that, for physical reasons, the ratio of road-to-river sinuosity should be ~1 in canyons, >1 in mountains, and <1 in plains and that sociohistorical influences may have modified these physically based sinuosity patterns, particularly in contemporary plains. We assessed these hypotheses with data from nonurban, intermediate-size roads and small- to intermediate-size rivers from 20 regions in France, Germany, the UK, and eastern and western USA. Distinct sociohistorical differences among regions affected the evolution of road-network geometry, but modern engineering approaches homogenized these legacies. Contemporary road sinuosity reffects former demands for scenic roads in US mountains and different historical inheritance practices in northern and southern Germany. Contemporary river sinuosity reffects physical constraints in canyons and mountains, but major historical, socioeconomic, and cultural differences among regions and countries in plains. We conclude that: 1) un- derstanding the physical context that complicates sociohistorical analyses is essential for formulating hypotheses; 2) tests of such hypotheses may help define region-specific priorities and targets for ecological restoration; 3) link- ing land change with physical and sociohistorical drivers requires multiple conceptual models; and 4) changes in social, economic, cultural, religious, or political systems occur at different rates, more stochastically, and with fewer predictable consequences, than changes in ecological systems.
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- DOI
- DOI : 10.1086/688494
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- The alkyl glycerol ether lipid composition of heterotrophic sulfate reducing bacteria strongly depends on growth substrate
- auteur
- Arnauld Vincon-Laugier, Vincent Grossi, Muriel Pacton, Gilles Escarguel, Cristiana Cravo-Laureau
- article
- Organic Geochemistry, 2016, 98, pp.141-154. ⟨10.1016/j.orggeochem.2016.05.015⟩
- resume
- Bacterial non-isoprenoid alkyl glycerol ether lipids (AGEs) are widespread in the environment but little is known about their biological precursors and mode of formation as a function of varying growth condi- tions. Here, we searched for the presence of AGEs in five pure strains of mesophilic (growth temperature between 20 and 40 C) and heterotrophic sulfate reducing bacteria from the family Desulfobacteraceae grown on a wide range of hydrocarbons and organic acids as sole carbon and energy source. Gas chro- matography–mass spectrometry (GC–MS) analysis of hydrolyzed cells revealed the presence of mono- alkyl glycerols (MAGEs) in one Desulfatiferula species and of MAGEs and dialkyl glycerols (DAGEs) in two Desulfatibacillum species. Species from the genus Desulfococcus did not produce AGEs. The ether lipid composition appeared strongly dependent on the nature and the chain length of the carbon substrate, with few to > 50 homologues of AGEs formed from a single substrate. Growth on long chain n-alkyl com- pounds (C14 to C18 alk-1-enes and fatty acids) generated a much lower diversity of MAGEs and DAGEs than short chain substrates (nonanoate, octanoate and pyruvate) or isoprenoid alkenes (phytadienes). Such variation in alkyl glycerol production could be linked to the distinct pathways involved in the meta- bolism of the different substrates. Despite this substrate-dependent AGE composition, the average chain length and level of branching of each class of ether lipid remained remarkably stable whatever the growth substrate and the number of MAGE and DAGE homologues formed, indicating a compositional control of ether lipids by heterotrophic bacteria to maintain optimal membrane properties.
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- Journal articles
- DOI
- DOI : 10.1016/j.orggeochem.2016.05.015
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- titre
- Larval competition risk shapes male– male competition and mating behavior in an anuran
- auteur
- Hugo Cayuela, Thierry Lengagne, Bernard Kaufmann, Pierre Joly, Jean-Paul Léna
- article
- Behavioral Ecology, 2016, 27 (6), pp.1726-1733. ⟨10.1093/beheco/arw100⟩
- resume
- Mate preference was long assumed to be static and open-ended. However, a growing body of evidence actually suggests that the predominant factor in mate choice fluctuates due to the context dependence of the factors involved in sexual selection. In particu- lar, fluctuation in the local environment, the density of individuals, and the presence of heterospecifics can all alter the strength, form, or direction of sexual selection by shaping the fitness costs and benefits of the traits that mediate male–female interactions. Amphibians constitute useful biological models to examine context dependence in sexual selection as the availability of suitable breeding resources may significantly impact the cost–benefit trade-off between mating strategies. Using an experimental approach, we examined how the risk of larval competition in breeding ponds affects pond occupancy, male–male spacing behavior, and spawn- ing decisions in an anuran, the yellow-bellied toad (Bombina variegata). Then, we examined how female mate choice is affected by male body condition and how the risk of larval competition might influence females when choosing a mate. Our results indicate that male pond preference is strongly affected by the presence of conspecific tadpoles. Males preferentially selected ponds free of tadpoles, and spawning mainly occurred in these same ponds. This preference influenced male spacing behavior by enhancing the proximity of competing males when the availability of good-quality sites was experimentally manipulated, which had further significant consequences on females’ choice of mate. The article also discusses the evolutionary causes and consequences of such context- dependent mate choice in amphibians and beyond.
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- Journal articles
- DOI
- DOI : 10.1093/beheco/arw100
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