Microbial processes supported by hydrogen and carbon monoxide produced in soil

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The United Nations Organization declared 2015 the International Soil Year to raise awareness of the importance of protecting soils that support essential services to humankind, including food security and mitigation of greenhouse gases emissions. These challenges are directly in line with the mission of modern microbiologists who benefit from extremely powerful technological tools to disentangle factors shaping the structure of soil microbial communities. One ambition of this research sector is to take control of microorganisms by engaging them into the ecosystem services they support. The overarching objective of the proposed research program is to identify and characterize soil bacteria that capture molecular hydrogen (H2) and carbon monoxide (CO). These microorganisms, which are ubiquitously found in all terrestrial ecosystems, support globally-relevant ecosystem services to humanity since they are responsible for 80% and 15% of the total losses of atmospheric H2 and CO. Examination of the factors influencing their distribution and activity in the environment is of particular importance since the absence or inactivation of these bacteria would have dramatic consequences on the climate on Earth. Our team is among the few experts worldwide studying microorganisms consuming atmospheric H2 and CO and our recent work suggests that these bacteria play a previously unsuspected role in the modulation of biogeochemical cycles, including carbon turnover and soil-to-air exchanges of methane contributing to greenhouse effect. These effects would be particularly important in agroecosystems with sequences of crop rotation with legumes that produce enormous amounts of H2 and CO in soil. Using sophisticated tools such as isotopic tracers and metagenomics, we will define how H2 and CO reallocate carbon from root exudates to soil microbial communities and the benefits they bring to the soil. As Canada is one of the world's largest pulse producers, this research will allow the country to benefit more from the ecosystem services their practices support, including the capture of greenhouse gases and soil biodiversity. These efforts will enable Canada to maintain its leadership in sustainable food production for present and future generations.