The majority of marine dissolved organic carbon (DOC) is resistant to biological degradation and thus can remain in the water column for thousands of years, constituting carbon sequestration in the ocean. To date the origin of such recalcitrant DOC (RDOC) is unclear. A recently proposed conceptual framework, the microbial carbon pump (MCP), underlines the microbial transformation of organic carbon from labile states to recalcitrant states. However, there is still lack understanding about the molecular transformation mechanism of RDOC from the gene to the ecological level. This project mainly focuses on the transformation and regulation of RDOC by marine micro-organisms. The main targets comprised three parts: 1) investigate microbially mediated transformation of different substrates (from simple to complex) to contribute to DOM pool using incubations experiment of single bacterium and natural environmental microbial assembly, respectively; 2) study eutrophic/oligotrophic environmental microbial transformation and metabolism of phytoplankton -derived organic matter, and the coupling between the succession of microbial communities and the transformation of DOM molecules; 3) figure out the correspondence relationship between DOM molecules and microbial community on a spatiotemporal scale; 4) link microbial functional genes, metabolic activity and environmental DOC molecules. This project would deepen our understanding of the microbial mediated biogeochemical cycle in the ocean, and shed light on the microbial and environmental response processes to global change in the future.
（Edited by Qiang Zheng）
(Editing Contact：xjz@xmu.edu.cn)