Link between microbial diversity, stability of microbial communities and soil organic matter turnover

Soil microbial communities act as important agents of the biological soil functioning, particularly through their involvements in the transformations of biogeochemical cycles (C, N, P…). In agro-ecosystems, the diversity of these communities is affected by perturbations associated to agricultural practices, and the significance of these modifications in terms of preservation of biological functioning and sustainability of agricultural systems has emerged as a central issue in the environmental sciences. Whereas the role of biodiversity has been well studied for macroorganisms, in particular for plants; the biodiversity/activity relationship is still largely unknown for soil microorganisms. …

Lien entre la diversité microbienne, la stabilité des communautés microbiennes et le turnover des matières organiques du sol

Soil microbial communities act as important agents of the biological soil functioning, particularly through their involvements in the transformations of biogeochemical cycles (C, N, P…). In agro-ecosystems, the diversity of these communities is affected by perturbations associated to agricultural practices, and the significance of these modifications in terms of preservation of biological functioning and sustainability of agricultural systems has emerged as a central issue in the environmental sciences. Whereas the role of biodiversity has been well studied for macroorganisms, in particular for plants; the biodiversity/activity relationship is still largely unknown for soil microorganisms. …

Shifts in microbial diversity through land use intensity as drivers of carbon mineralization in soil

10 pages; International audience; Land use practices alter the biomass and structure of soil microbial communities. However, the impact of land management intensity on soil microbial diversity (i.e. richness and evenness) and consequences for functioning is still poorly understood. Here, we addressed this question by coupling molecular characterization of microbial diversity with measurements of carbon (C) mineralization in soils obtained from three locations across Europe, each representing a gradient of land management intensity under different soil and environmental conditions. Bacterial and fungal diversity were characterized by high throughput sequencing of ribosomal genes. Carbon cycl…

How do microbial communities in top-and subsoil respond to root litter addition under field conditions?

Abstract Contrasting microbial community composition and activity at different soil depths may affect root litter decomposition. These effects have up to now been investigated mainly in laboratory studies, which may not be able to take into account complex in situ conditions. Our study aimed to analyze the composition and activity of microbial communities after addition of 13 C labeled wheat root litter to a loamy soil under grassland at 30, 60 and 90 cm depths, during a three-year field experiment. We investigated the dynamics of bacterial and fungal abundances and community structures by DNA genotyping and pyrosequencing of 16S and 18S rDNAs. The genetic structures of bacterial and fungal…

Erosion of biodiversity affects the stability of soil microbial communities

Anthropogenic activities have led to a significant modification/reduction of biodiversity. By observing this erosion, the understanding of the relationship between biodiversity and ecosystem functioning has emerged as a central issue in ecological and environmental sciences during the last decade. This relationship between diversity-stability-function has been extensively studied by plant ecologists, but remains largely unexplored for soil microorganisms. In this context, we studied the impact of an erosion of biodiversity on the stability of soil microbial communities (i.e. resistance and resilience) in response to two perturbations: a residual metallic stress (mercury input at 20 ppm) and…

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Distribution spatiale et traduction fonctionnelle de la diversité microbienne des sols

Le sol, après avoir longtemps été considéré comme un support de construction et de production, est maintenant légitimé comme un des derniers remparts pour la biodiversité terrestre. Parmi les organismes indigènes du sol, les microorganismes et notamment les bactéries sont les plus abondants et diversifiés avec plusieurs milliards d’individus représentant plusieurs millions d’espèces différentes par gramme de sol. De plus, ces microorganismes ont un rôle dans les cycles biogéochimiques des éléments majeurs (C, N, P…) et donc dans les services écosystèmiques que peut rendre le sol (recyclage éléments minéraux, qualité de l’atmosphère et de l’eau, production primaire…). Par conséquent, afin d’…

Stability of soil microbial structure and activity depends on microbial diversity

Despite the central role of microbes in soil processes, empirical evidence concerning the effect of their diversity on soil stability remains controversial. Here, we addressed the ecological insurance hypothesis by examining the stability of microbial communities along a gradient of soil microbial diversity in response to mercury pollution and heat stress. Diversity was manipulated by dilution extinction approach. Structural and functional stabilities of microbial communities were assessed from patterns of genetic structure and soil respiration after the stress. Dilution led to the establishment of a consistent diversity gradient, as revealed by 454 sequencing of ribosomal genes. Diversity …

La perte de diversité affecte la stabilité structurelle et fonctionnelle des communautés microbiennes du sol

Les activités anthropiques impactent fortement la diversité des communautés microbiennes du sol. La question se pose de savoir dans quelle mesure ces modifications de diversité peuvent remettre en cause la capacité des sols à assurer les services dont dépendent les sociétés humaines. Pour répondre à cette question, une meilleure compréhension de la relation diversité-stabilité-fonction est indispensable. En 1999, Yachi et Loreau développent le concept d'assurance écologique selon laquelle une forte diversité d'espèces dans un écosystème permet une meilleure stabilité de son fonctionnement. Cette relation a largement été étudié chez les végétaux mais reste encore inconnue chez les microorgan…

Lasting effect of solid waste composts on soil microbial communities

EABIOME; Lasting effect of solid waste composts on soil microbial communities. 16. International Symposium on Microbial Ecology - ISME16

Qu’attendre des recherches en microbiologie du sol ?

SPE EA EcolDur GenoSol MERS IPM Résumé du livre : La fertilité des sols est au carrefour des enjeux de sécurité alimentaire, de protection de l’environnement et de rentabilité économique de l’activité agricole. Cet ouvrage présente les résultats d’une réflexion prospective sur le contexte de la fertilisation dans les 5-10 ans à venir. Il définit les besoins en termes de méthodes et d'outils pour la gestion des cycles biogéochimiques et le raisonnement de la fertilisation en agriculture. Mots clés du livre : agriculture - agronomie - eau - effluent - engrais - environnement - fertilisation - pollution - prévention - production végétale - prospective - sol Description du chapitre 10 (partie 3…

Development and dissemination to operational stakeholders of integrative tools for chemical and biological measurements in watercourses to monitor the impact of pesticides according to agricultural practices and their evolution

The results of the Impact-CE project highlight the specific contribution of various integrative tools to have a more complete vision of the chemical and biological impact of pesticides on watercourses. In addition to grabe sampling, which gives a quantitative and instantaneous view of contamination, these tools provide more representative information over time, which makes them better tools for prioritising basins that contribute to contamination. They are also more robust for reporting interannual changes in agricultural practices, even if it may remain difficult to dissociate the effect of limited changes in practices from that of significant climatic variations. The results also confirm …