Linking soil microbial diversity, nitrogen cycling and greenhouse gas emissions

Microbial communities have a central role in ecosystem processes by driving the Earth’s biogeochemical cycles. However, the importance of microbial diversity for ecosystem functioning is still debated. This talk will highlight how trait-based approaches can help understanding the role of microbial diversity in soil functioning. For this purpose, denitrification, a microbial process involved in N-cycling, was selected as a model functional trait. Denitrification is a microbial respiratory process during which soluble nitrogen oxides are used as alternative electron acceptor when oxygen is limiting. It is involved in ecosystem services such as filtering but also disservices. Thus, denitrification can results in considerable losses of nitrogen, which is the most limiting nutrient for crop production in agriculture. It is also responsible for emissions of nitrous oxide, one of the six greenhouse gases considered by the Kyoto protocol. Using both naturally assembled and artificially manipulated communities, I will show how the diversity of the denitrifier community relates to process rates and N2O emissions. This talk will also illustrate how the analysis of spatial patterns of traits can help bridging microbial community ecology and ecosystem process in terrestrial environments