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Press Info item.
31/10/2008
National inventory and mapping of microbial biodiversity in soils
Special "Biodiversity"
In 2006, INRA researchers in Dijon initiated an ambitious research programme, ECOMIC-RMQS, designed to analyse the abundance and diversity of soil micro-organisms in France. The initial results obtained have revealed the distribution of the density and diversity of soil microbial communities, and the significant influence of pedological parameters (soil pH, texture, etc.) and anthropogenic activities (agricultural use of soils) on regulation of this biodiversity, and the positive correlation between landscape diversity and that of microbial communities. This research programme will not only enable an inventory of the biodiversity of French soils, but also provide a clearer understanding of the impact of different uses (agricultural, industrial, urban) on this biodiversity.
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The RMQS network, 2200 sites throughout France
The Soil Quality Measurement Network (Réseau de Mesure de la Qualité des Sols, RMQS) set up in 2002 by GISSOL, provides a national framework to observe changes in soil quality. This network for the systematic measurement and monitoring of pedological parameters, managed by the INFOSOL Unit (Orleans Research Centre) is based on the sampling and description of soils from some 2200 sites spread uniformly throughout France, according to a 16 km x 16 km square mesh. At the centre of each mesh is a soil sampling device that will be renewed every 10 years. Within this network, the standard tools used to monitor the quality of French soils consist mainly in testing its physical and chemical characteristics. The aim of the network is enable the early detection of the appearance soil quality deterioration and the trends affecting it. In 2006, microbial ecologists from INRA in Dijon initiated the ECOMIC-RMQS research programme which, within this surveillance network, is responsible for monitoring the abundance and diversity of soil micro-organisms in France.
Micro-organisms and soil quality
Because of their taxonomic and functional diversity, soil micro-organisms play a fundamental role in soil functioning: carbon and nitrogen cycles, the bioavailability of nutrient elements, the degradation of organic pollutants, the retention of metallic pollutants, action on soil structure, etc. On the other hand, communities of micro-organisms are likely to integrate all the environmental stresses that affect the soil. In this respect, they may thus constitute early indicators of changes to soil quality. It thus seems essential to develop monitoring tools that can reflect the impacts of different pressures (changes to use or practices, atmospheric pollution, climate change, etc.) on soil microbial communities and their biodiversity.
The initial results of the ECOMIC-RQMS project
In this context, the ECOMIC-RMQS project, funded by the ADEME and ANR and coordinated by the INRA-University of Burgundy Joint Research Unit for Soil Microbiology and the Environment in Dijon, was set up to meet several high priority objectives:
• to characterize and evaluate microbial biodiversity in French soils,
• to analyze the geographical distribution profiles of this diversity,
• to classify the pedo-climatic and anthropogenic parameters influencing this biodiversity,
• to evaluate the ecological consequences of changes to biodiversity.
In the context of this project, molecular biology tools are used to perform direct measurements of microbial density and diversity on DNA extracted from RMQS soil samples. The initial results obtained by the ECOMIC-RQMS programme have thus demonstrated:
• a heterogeneous distribution of density, spatially structured at a large scale (Figure 1) and the diversity of soil microbial communities (Figure 2),
• the significant influence of certain pedological parameters (soil pH, texture, etc.) and anthropogenic factors (agricultural use of soils) on regulation of this biodiversity,
• a positive correlation between landscape diversity and the diversification of soil microbial communities at a large scale. Indeed, the researchers have demonstrated a area-species relationship that is more significant when the landscape is diversified in terms of soil type, type of soil use, climate and geomorphology.
Because of the ambitious objectives of this research programme, which requires the sharing of molecular biology tools as well as of the management and conservation of biological samples libraries (soil DNA) and the associated data thus generated, in 2008 the INRA researcher team in Dijon created a dedicated logistic and technical platform: GenoSol. This mission of this platform is to conserve, make available and characterize microbial genetic resources based on DNA extracted from large scale soil sampling efforts (soil monitoring network, environmental research observatories, workshop sites, etc.). In the longer term, implementation of this facility should represent a reference for the analysis of microbial biodiversity, so as to enable improved estimates of the sustainability of different methods for soil management and use.
For more information about GenoSol : http://www.dijon.inra.fr/plateforme_genosol
Each square characterises the genetic structure of a bacterial community.
The more the squares are contrasted in terms of size or shading, the more the genetic structures of bacterial communities are different.
For example, bacterial communities in south-west Brittany are very similar, but differ markedly from those in south-eastern France.
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