Auteurs, date et publication :
Auteurs J. F. Le Galliard , J. M. Guarini , F. Gaill
Date : 2025
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENS #PLANAQUARésumé
Un ensemble coordonné de plateformes ouvertes la recherche internationale en écotoxicologie : Analyse et Expérimentation sur les Ecosystèmes – France. Colloque « Construire le réseau ANTIOPES 2.0 - La toxicologie et l’écotoxicologie prédictives : de l’appliqué à l’opérationnel »
Auteurs, date et publication :
Auteurs Christian Mougin , Didier Azam , Thierry Caquet , Nathalie Cheviron , Samuel Dequiedt , Jean-François Le Galliard , Olivier Guillaume , Sabine Houot , Gérard Lacroix , Francois Lafolie , Pierre-Alain Maron , Radika Michniewicz , Christian Pichot , Lionel Ranjard , Jacques Roy , Bernhard ZELLER , Jean Clobert , Andre Chanzy
Date : 2016
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENS #PLANAQUARésumé
Fungi are the main organisms responsible for plant biomass degradation in soils. While many studies have evaluated the impact of tree species on the taxonomic diversity of soil fungi, very few of them have addressed their functional gene diversity. In the present study, we assessed the impact of tree species, differing with respect to litter quality, and sampling dates on the diversity of four expressed fungal gene families: one housekeeping gene used as taxonomic marker and three others encoding key enzymes implicated in lignocellulose degradation selected as functional markers. This was performed by the high throughput sequencing of gene-fragments amplified from forest soil mRNA using fungal specific primers. Messenger RNAs were extracted from 10 soil samples collected over two seasons in plots planted with either the conifer Picea abies or the angiosperm Fagus sylvatica in a common garden experiment. Independently of the gene-family, less than 20% of the fungal transcripts were identified in both forest types. For all four fungal gene-families, variance partitioning identified the tree species and its interaction with the sampling plot as the factors that contributed most to global gene diversity (between 29% and 32%), while the sampling dates accounted for less than 9%. Further analysis of the contribution of soil proprieties revealed that the tree species-generated C/N ratio is the most important factor driving functional gene distribution (between 6% and 29% of the variation explained). Similarly, for each fungal gene family, statistical analyses identified tree species as the main factor responsible for variations in similarity between samples (as estimated by the Bray-Curtis beta diversity index). These results highlight that tree species, differing with respect to litter quality, selected different soil fungal communities expressing different set of genes involved in plant organic matter degradation. (C) 2016 Elsevier Ltd. All rights reserved.
Auteurs, date et publication :
Auteurs Florian Barbi , Elsa Prudent , Laurent Vallon , Marc Buee , Audrey Dubost , Arnaud Legout , Roland Marmeisse , Laurence Fraissinet-Tachet , Patricia Luis
Publication : Soil Biology and Biochemistry
Date : 2016
Volume : 100
Pages : 149-159
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENS #FORET BreuilRésumé
The "PLAteforme expérimentale Nationale d'écologie
AQUAtique" is a multi-scale experimental infrastructure created in 2011
to make possible the analysis of human disturbance on aquatic
biodiversity, community structure, and ecosystem functioning. It is
funded by the "Investissements d'avenir Equipex" program and is partner
of the ANAEE-France research infrastructure. PLANAQUA provides the
scientific community with access to experimental highly instrumented
platforms available year round through calls for projects open to all
researchers around the world. It includes: 1) Microcosms (1-6 L),
developed for studying plankton ecology and physiology under highly
controlled environmental conditions in the dedicated laboratory or in
the climatic rooms of the Ecotron IleDeFrance. Organisms and ecosystems
activity and dynamics are precisely monitored by a series of dedicated
sensors and instruments. 2) Mesocosms (1-15 m3), have a high degree of
replication. They are installed outdoors and can house complex
communities of organisms. Among them a series of twelve is equipped with
beaters that generate waves, making possible to control the physical
structure of the water column thus to study the link between physical
constraints and functioning of aquatic systems. 3) Macrocosms, sixteen
artificial lakes (650 m3) dedicated to understand the functioning of
complex natural communities with heterogeneous spatial distributions;
they will allow ascertaining the consequences of anthropogenic pressures
on biodiversity, up to the top of the food chains. They are equipped
with automated sensors and data loggers for high-frequency data
collection of the main physical-chemical parameters. PLANAQUA is located
at the CEREEP research center (CNRS-ENS, UMS 3194) near Paris.
Keywords: Aquatic ecosystems functioning and dynamics, plankton
eco-physiology, biodiversity, environmental changes, experimental
platform, multi-scale studies, instruments and sensors
Auteurs, date et publication :
Auteurs Sarah Fiorini , Alexis Millot , Simon Chollet , Florent Massot , Jean-François Le Galliard , Emma Rochelle-Newall , Gerard Lacroix
Date : 2018
Volume : 20
Pages : 9724
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENS #PLANAQUARésumé
In the context of increasing population and decreasing acreages, the reduction in crop yields induced by tropospheric ozone should be better evaluated. Therefore, ozone-resistant and ˗sensitive tobacco (cv. Bel-B and Bel-W3), barley and rapeseed plants were submitted to ozone-enriched air, during pre-flowering period. Six ozone concentrations (ranging from 30 to 130 ppb for six hours during the photoperiod) and two treatment durations (1 or 2 weeks) were applied. These treatments correspond to low, moderate and high exposure levels that occurs in France. Several leaf parameters were measured: necrosis development, chlorophyll content, chlorophyll fluorescence (Fv/Fm, ΦPSII), gas exchange (carbon assimilation and leaf conductance), seed yield, and fatty acid composition in cell membranes. The fatty acid composition was used to calculate the "Omega-3 index", a biomarker based on stress-induced changes in leaf 18:3 content, developed to assess soil quality. To estimate the oxidative load in leaf tissues, quantification of targets of oxidative stress (such as intracellular proteins carbonylation) was rather used instead poorly reproductible ROS quantification. Results show that ozone treatments decrease chlorophyll content and omega-3 index. The extent of the declines and the threshold levels of ozone exposure triggering the declines observed in the different plant species studied will be discussed. Direct continuation of this study, will involve a water stress applied to the plants subsequent to the ozone treatments. The same physiological approach will then be used to characterize the plant responses to the combined stress treatments, to assess their resilience to drought after an ozone pollution episode.
Auteurs, date et publication :
Auteurs Ruben Puga-Freitas , Matthieu Bagard , Luis Leitao , Elodie Merlier , Christophe Espinasse , Anne Repellin , Jean-Jacques Bessoule , Marina Le Guédard , Amandine Hansart , Simon Chollet , Juliette Leymarie
Date : 2018
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENSRésumé
Modulations of advective gas fluxes at the soil–atmosphere interface were investigated using an enhanced experimental setup developed to perform tracer gas percolation experiments through unsaturated soil columns under well-controlled conditions associated with long-term and high-resolution monitoring. The setup design includes the effect of watering and evaporation cycles, barometric pressure fluctuations, variations in the injection pressure, and plant metabolism. Although injected at a constant flux at the base of the columns, SF6 surface fluxes varied on a timescale of hours to days. These modulations are controlled by (a) barometric pressure, (b) water content and distribution, and (c) plant metabolism. All three mainly act on the pressure gradient. Surface gas fluxes decrease under drying conditions, which increases gas porosity and the relative gas permeability and lowers the pressure gradient. Respiration of plant roots is shown to be responsible for daytime–nighttime oscillations of the tracer flux. During nighttime, O2 consumption and CO2 production locally lowers the pressure gradient up to the root zone due to the higher solubility of CO2 in pore water, resulting in an increased SF6 flux at the surface. During daytime, enhanced water loss by evapotranspiration associated with photosynthesis dominated the respiration effect and resulted in decreasing surface gas fluxes, as generally shown for drying conditions. Surface gas fluxes are therefore controlled by combined physical, chemical, and biological processes. This has important consequences, notably when discrete flux measurements are integrated in space and/or in time to quantify emissions or when used for detecting, identifying, or monitoring underground gas sources.
Auteurs, date et publication :
Auteurs Clement Alibert , Eric Pili , Pierre Barre , Florent Massol , Simon Chollet
Publication : Vadose Zone Journal
Date : 2025
Volume : 19
Issue : 1
Pages : e20018
Catégorie(s)
#ANR-Citation #CNRS #Ecotron IleDeFrance #ENSRésumé
Biogeochemical Cycles: Ecological Drivers and Environmental Impact is a collection of the latest information on the techniques and methods currently used in this field, focusing on biological and/or ecological effects of biogeochemical elemental cycles including carbon, nitrogen, major and trace elements, chemical weathering on multiple scales of nanometers to watersheds, and advances in technology of studying these processes.Volume highlights include:- Remote sensing and modeling techniques used to quantify changes in the ecosystem/s productivity, and microscopic techniques to estimate the extent of weathering - Novel isotopic techniques to assess changes in trace elemental cycles as influenced by the changing climate, and plant-mediated effect of climate change on major elemental cycles - Impact of climate change and other anthropogenic influences in agricultural and extreme (frontier) environmentsBiogeochemical Cycles: Ecological Drivers and Environmental Impact is a valuable resource for students, researchers and professionals in the field of biogeosciences, hydrology, ecology, earth and planetary surface processes, volcanology, petrology, geochemistry, mineralogy, soil science, agricultural science, climate change and environmental science.
Auteurs, date et publication :
Auteurs Katerina Dontsova , Zsuzsanna Balogh-Brunstad , Gaël Le Roux
Date : 2020
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENSRésumé
The determinants of intraspecific stoichiometric variation remain difficult to elucidate due to their multiple origins (e.g. genetic vs. environmental) and potential interactive effects. We evaluated whether two size-selected lines of medaka (Oryzias latipes) with contrasted life-history strategies (small- and large-breeder lines with slow growth and early maturity vs. fast growth and late maturity) differed in their organismal stoichiometry (percentage and ratios of carbon [C], nitrogen [N] and phosphorus [P]) in a mesocosm experiment. We also tested how size-selection interacted with environmental conditions (i.e. two levels of fish density and light intensity), body condition and sex. Results showed that large-breeder fish were significantly N-enriched compared to small-breeders, while the two size-selected lines did not differ in body P composition. Size-selection interacted with density – high density only affected small-breeders leading to decreasing %C and C: N – and with sex – large-breeder females had higher %C and C:N values than large-breeder males. Finally, C:P and N:P ratios increased with body condition due to decreasing %P. Overall, our results show that the ecological consequences of size-selective mortality extend to organismal stoichiometry and may, from there, change nutrient cycling and ecosystem functioning.
Auteurs, date et publication :
Auteurs Charlotte Evangelista , Beatriz Diaz Pauli , Leif Asbjørn Vøllestad , Eric Edeline
Publication : Science of The Total Environment
Date : 2020
Volume : 724
Pages : 138193
Catégorie(s)
#ANR-Citation #CNRS #Ecotron IleDeFrance #ENSRésumé
Organic matter management is key to sustain ecosystem services provided by soils. However, it is rarely considered in a holistic view, considering local resources, agro-environmental effects and harmonization with farmers’ needs. Organic inputs, like compost and biochar, could represent a sustainable solution to massive current challenges associated to the intensification of agriculture, in particular for tropical regions. Here we assess the potential of agricultural residues as a resource for farmer communities in southwestern India to reduce their dependency on external inputs and sustain ecosystem services. We propose a novel joint evaluation of farmers’ aspirations together with agro-environmental effects of organic inputs on soils. Our soil quality evaluation showed that biochar alone or with compost did not improve unilaterally soils in the tropics (Anthroposol, Ferralsol and Vertisol). Many organic inputs led to an initial decrease in water-holding capacities of control soils (-27.3%: coconut shell biochar with compost on Anthroposol). Responses to organic matter inputs for carbon were strongest for Ferralsols (+33.4% with rice husk biochar), and mostly positive for Anthroposols and Vertisols (+12.5% to +13.8% respectively). Soil pH responses were surprisingly negative for Ferralsols and only positive if biochar was applied alone (between -5.6% to +1.9%). For Anthroposols and Vertisols, highest increases were achieved with rice husk biochar + vermicomposts (+7.2% and +5.2% respectively). Our socio-economic evaluation showed that farmers with a stronger economical position showed greater interest towards technology like biochar (factor 1.3 to 1.6 higher for farmers cultivating Anthroposols and/or Vertisols compared to Ferralsols), while poorer farmers more skepticism, which may lead to an increased economical gap within rural communities if technologies are not implemented with long-term guidance. These results advocate for an interdisciplinary evaluation of agricultural technology prior to its implementation as a development tool in the field.
Auteurs, date et publication :
Auteurs Severin-Luca Bellè , Jean Riotte , Norman Backhaus , Muddu Sekhar , Pascal Jouquet , Samuel Abiven
Publication : PLOS ONE
Date : 2022
Volume : 17
Issue : 1
Pages : e0263302
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENSRésumé
Soil organic carbon is regulated by a dynamic interaction of vegetation inputs, organic matter degradation and stabilization processes in soils, and its redistribution in the landscape. Tropical ecosystems are highly important in terms of carbon stored in vegetation and soil, but many processes of the soil carbon cycle in the tropics are yet to be fully understood. Here, we studied soil organic carbon stocks and quality in small-scale tropical, sub-humid and semi-arid watersheds along a climate gradient in southwestern India with varying vegetation and geology to identify major drivers of soil organic carbon dynamics in three prevalent soil types (Lixisol, Vertisol and Ferralsol) under shrubland and dry deciduous forest. We used a combination of organic carbon analysis (total organic carbon content, 13C, C:N), mid-infrared spectroscopy and soil property information (bulk density, texture, oxides, pH, cation-exchange capacity). Soil organic carbon stocks in these watersheds showed a substantial range from 58.2 to 169.4 MgCha−1 in the first 60 cm, and the differences depended on local- to watershed-scale variations in vegetation type and history, geology, soil physio-chemical (clay, oxides) and biological (bioturbation) properties. Considerable parts of the organic carbon stored in these soils was found below 30 cm (up to 40%), stressing the importance of tropical subsoils. From our analysis of the soil organic carbon quality and literature data on paleoclimate and vegetation, we could identify land-use changes in these watersheds, from tropical moist evergreen forests, forest-savannah transitions and plantations to secondary regrowth forest over time. Our study provides new data and insights into the local-scale drivers of soil organic carbon quantity and quality of tropical, sub-humid and semi-arid watersheds under shrubland and dry deciduous forest with varying geology and soil types.
Auteurs, date et publication :
Auteurs Severin-Luca Bellè , Jean Riotte , Muddu Sekhar , Laurent Ruiz , Marcus Schiedung , Samuel Abiven
Publication : Geoderma
Date : 2022
Volume : 409
Pages : 115606