Résumé
In soils characterized by nutrient-poor conditions trees have developed strategies to maximize the exploration of the environment through their root system. Notably, in shallow soils, trees adopt a deeprooting strategy to access appropriate levels of water and nutrients from the bedrock. Despite the critical importance of microorganisms in nutrient access in topsoil, understanding their involvement in subsoil was rarely addressed. Our study provides the first comprehensive picture of the bacterial communities colonizing deep roots at the bedrock interface. Particularly, we aimed at deciphering if the subsoil edaphic conditions allowed the enrichment of specific bacterial communities in the rhizosphere. To answer such questioning, we focused on a shallow soil dominated by deep-rooting beech trees (Fagus sylvatica). The taxonomic and functional structures of bacterial communities were investigated through 16S rRNA-pyrosequencing analyses and in vitro bioassays on culturable representatives isolated from the saprolite, the limestone rocks and the roots penetrating those two compartments at the bedrock interface. Our taxonomic analyses revealed a rhizosphere effect, with no difference between the limestone- and saprolite-rhizosphere bacterial communities. Notably, our functional assays highlighted a significant enrichment of bacteria effective at mineral weathering in the limestone-rhizosphere compared to the surrounding environment, whereas organic matter decomposing bacteria were exclusively enriched in the saprolite-rhizosphere. Altogether our results suggest that tree roots select specific bacterial communities in subsoil as potential allies to improve nutrient availability and tree nutrition.
Auteurs, date et publication :
Auteurs O. Nicolitch , Y. Colin , M.-P. Turpault , L. Fauchery , S. Uroz
Publication : Soil Biology and Biochemistry
Date : 2025
Volume : 115
Pages : 109-123
Catégorie(s)
#FORET Montiers #INRAEAuteurs, date et publication :
Auteurs Y. Colin , O. Nicolitch , J. D. Van Nostrand , J. Z. Zhou , M.-P. Turpault , S. Uroz
Publication : Scientific Reports
Date : 2025
Volume : 7
Issue : 1
Catégorie(s)
#FORET Montiers #INRAEAuteurs, date et publication :
Auteurs Carlos Barata , Bruno Campos , Claudia Rivetti , Gerald A. LeBlanc , Stephanie Eytcheson , Stephanie McKnight , Marysia Tobor-Kaplon , Selinda de Vries Buitenweg , Suhyon Choi , Jinhee Choi , Elena I Sarapultseva , Marie-Agnès Coutellec , Maïra Coke , Pascal Pandard , Arnaud Chaumot , Hervé Quéau , Nicolas Delorme , Olivier Geffard , Fernando Martínez-Jerónimo , Haruna Watanabe
Publication : Science of The Total Environment
Date : 2017
Volume : 579
Pages : 1073-1083
Catégorie(s)
#INRAE #PEARLRésumé
Cold aquatic ecosystems such as high altitude alpine lakes are expected to act as long-term sinks of polychlorinated biphenyls (PCBs), the burden of which might even be intensified by global warming. Because the physical, chemical, and biological structures of high altitude lakes are highly responsive to climate change, both PCB exposure and bioaccumulation are likely to be strongly altered in the near future. Yet, in the absence of mechanistic knowledge of the processes regulating fish contamination with PCB in such ecosystems, their fate cannot be predicted. The aim of this study was to investigate the relative roles of biomagnification and bioconcentration on the individual, seasonal, and between-site variability of fish PCB contamination in 2 alpine, high altitude lakes. The intra- and within-lake variability of fish PCBs was not related to differences in fish physiology (size, age, or lipid content) and only marginally tied to fish feeding habitats (assessed from fatty acid composition and δ13C) or trophic position (δ15N). These results suggested that the trophic pathway and biomagnification contributed little to the observed differences in fish PCB concentrations between lakes, seasons, and individuals. Moreover, the fish PCB levels did not depend on the total PCB concentration in the water, but the fish contamination dynamics during the spring thaw pointed to a significant role of dissolved PCBs during this season in both lakes. In high altitude lakes, low temperatures might contribute to kinetically limit equilibrium with dietary PCBs, thereafter favouring bioconcentration over biomagnification pathways by which fish become contaminated with PCBs.
Auteurs, date et publication :
Auteurs Marie-Elodie Perga , Yann-Michel Nellier , Nathalie Cottin , Philippe Fanget , Emmanuel Naffrechoux
Publication : Inland Waters
Date : 2017
Volume : 7
Issue : 1
Pages : 14-26
Catégorie(s)
#INRAE #OLARésumé
To investigate the relevance of biochemical parameters in biogeochemical mechanisms of the soil, it is important to gather data related to different soil types under different pedogeoclimatic conditions. In this study, we investigated on the calcareous agricultural soils in the Saiss plain (North Morocco). Four agricultural soils exposed to multi-metal (Cr, Cu, Zn, and Ni) and organic matter (OM) contamination as a result of irrigation with Oued Fez and Oued Sebou waters that are affected by urban and industrial activities around the city of Fez were studied and compared to a reference site irrigated with uncontaminated water. The study concerned soil physicochemical properties and the activity of a range of enzymes [phosphatase (PHOS), arylsulfatase (SULF), urease (UREA), arylamidase (AMID), b-galactosidase (GALA), glucosidase (GLUC), and laccase (LACA)] related to nutrients cycles. Pearson’s correlations between these parameters showed that soil enzymatic activities (PHOS, SULF, UREA, GALA, GLUC, and LACA) were correlated positively with heavy metals (Cu, Zn, and Cr) concentrations in the soil and also with dissolved organic carbon (DOC), and negatively with the aromaticity (AROM) of these compounds. Interestingly, analysis of intra-site correlations showed strong relationships among enzyme activities in the reference soil, while in contaminated soils, these activities were largely unrelated to each other. It was concluded that soil irrigation with heavy-metal- and OM-contaminated watercourses over decades has resulted in soils with high enzymatic activities function and nutrient turnover but altered relationships among geochemical cycles.
Auteurs, date et publication :
Auteurs Aziza Kouchou , Naoual Rais , Jeanne-Chantal Thoisy , Joëlle Duplay , Malika Ghazi , Françoise Elsass , Mustapha Ijjaali , Naïma El Ghachtouli
Publication : Soil and Sediment Contamination: An International Journal
Date : 2017
Volume : 26
Issue : 3
Pages : 259-276
Catégorie(s)
#BiochemEnv #INRAERésumé
Semantics for the Analysis and Experimentation on (continental) Ecosystems: AnaEE RI. Ontology & Semantic Web for Research. LifeWatch-ITA & EUDAT Workshop
Auteurs, date et publication :
Auteurs Christian Pichot
Date : 2017
Pages : np
Catégorie(s)
#Ecoinfo #INRAERésumé
Carbon (C) emissions from anthropogenic land use have accelerated climate change. To reduce C emissions, dynamic models can be used to assess the impact of human drivers on terrestrial C sequestration. Model accuracy requires correct initialisation, since incorrect initialisation can influence the results obtained. Therefore, we sought to improve the initialisation of a process-based SOC model, RothC, which can estimate the effect of climate and land-use change on SOC. The most common initialisation involves running the model until equilibrium (‘spin-up run’), when the SOC pools stabilise (method 1). However, this method does not always produce realistic results. At our experimental sites, the observed SOC was not at equilibrium after 10 years, suggesting that the commonly used spin-up initialisation method assuming equilibrium might be improved. In addition to method 1, we tested two alternative initialisations for RothC that involved adjusting the total or individual SOC pool equilibrium values by regulating the C input during the entire spin-up initialisation period (method 2) and initialising each SOC pool with recently measured SOC values obtained by SOC fractionation (method 3). Analysis of the simulation accuracy for each model initialisation, quantified using the root mean square error (RMSE), indicated that a variant of method 2 that involved adjusting the equilibrium total SOC to observed values (method 2-T) generally showed less variation in the individual SOC pools and total SOC. Furthermore, as total SOC is the sum of all SOC pools, and because total SOC data are more readily available than the individual SOC pool data, we conclude that method 2-T is best for initialising RothC.
Auteurs, date et publication :
Auteurs Nemo , K. Klumpp , K. Coleman , M. Dondini , K. Goulding , A. Hastings , Michael. B. Jones , J. Leifeld , B. Osborne , M. Saunders , T. Scott , Y. A. Teh , P. Smith
Publication : Environmental Modeling & Assessment
Date : 2017
Volume : 22
Issue : 3
Pages : 215-229
Catégorie(s)
#ACBB #ACBB Theix #INRAEAuteurs, date et publication :
Auteurs Gaétan Pottier
Date : 2017
Catégorie(s)
#INRAE #PEARLRésumé
In up-scaling studies, model input data aggregation is a common method to cope with deficient data availability and limit the computational effort. We analyzed model errors due to soil data aggregation for modeled SOC trends. For a region in North West Germany, gridded soil data of spatial resolutions between 1 km and 100 km has been derived by majority selection. This data was used to simulate changes in SOC for a period of 30 years by 7 biogeochemical models. Soil data aggregation strongly affected modeled SOC trends. Prediction errors of simulated SOC changes decreased with increasing spatial resolution of model output. Output data aggregation only marginally reduced differences of model outputs between models indicating that errors caused by deficient model structure are likely to persist even if requirements on the spatial resolution of model outputs are low.
Auteurs, date et publication :
Auteurs Balázs Grosz , Rene Dechow , Sören Gebbert , Holger Hoffmann , Gang Zhao , Julie Constantin , Helene Raynal , Daniel Wallach , Elsa Coucheney , Elisabet Lewan , Henrik Eckersten , Xenia Specka , Kurt-Christian Kersebaum , Claas Nendel , Matthias Kuhnert , Jagadeesh Yeluripati , Edwin Haas , Edmar Teixeira , Marco Bindi , Giacomo Trombi
Publication : Environmental Modelling & Software
Date : 2017
Volume : 96
Pages : 361-377
Catégorie(s)
#INRAE #RecordAuteurs, date et publication :
Auteurs B. Karimi , Chemidlin Prévost-Bouré , Samuel Dequiedt , Sébastien Terrat , Lionel Ranjard
Date : 2025
Volume : 41