Thawing carbon from land to sea: microbial degradation of organic matter and response to thawing permafrost in the northeast siberian land-shelf system
Arctic permafrost (PF) as vulnerable carbon stock to global warming is increasingly receiving attention due to significant importance in global climate change. Immense carbon stock is held in surface soils on land, coastal Pleistocene Ice Complex Deposit and sediment of shallow subsea in Arctic. Under global warming, the emission of greenhouse gases CO2 and CH4 from PF could further intensify global warming; however, the key link between thawing PF and greenhouse gas emission -microbial degradation remains poorly understood. Microbial degradation of organic matter and its response to thawing is conducive to understanding the biogeochemical carbon cycle and even the future prediction of greenhouse gases in Arctic. To better understand microbial mediation on PF-carbon feedback to global warming, this proposal aims to quantitatively estimate the microbial activity and metabolism in different types of PF (inland, coastal Ice Complex Deposit and marine sediment of subsea PF) from the northeast Siberian via multidisciplinary techniques including microcosm incubation, lipid-based stable isotope probing, modelled metabolic flux analysis and metabolomics. This proposal will improve the understanding of microbial ecosystem in response to thawing PF and their roles in biogeochemical carbon cycle in Arctic.