Elucidating the molecular mechanisms responsible for the formation of microbial-derived stable mineral-associated organic matter to improve carbon sequestration in agricultural systems

Increasing atmospheric carbon dioxide (CO2) concentrations are impacting the global climate and consequently there is a significant interest in soil carbon sequestration to mitigate the problem. Soil organic matter represents the largest terrestrial carbon reservoir, most of which is stabilized by the formation of mineral associated organic matter (MAOM). While a significant portion of MAOM in soils is formed by soil microbial activity, our understanding of microbial-derived MAOM formation processes is still limited due to the complexity of the soil environment. The aim of this project was to advance foundational knowledge on the functional mechanisms of microbial-derived MAOM formation for the optimization of environmental processes such as carbon sequestration. In this project, we collected microbe community DNA from several mineral-containing soil samples. Multiple kinds of minerals, including sand, sand+illite, and sand+kaolin were placed in mesh bags and incubated in different soil samples. The metagenome DNA was sequenced with 16S amplicon sequencing. The results from this project allow us to identify the key microorganisms and their functional pathways that are responsible for the formation of MAOM at the mineral surface. The outcome of this project provides new knowledge that we hope will catalyze new tools to enhance the carbon sequestration in soil.