Advances of Living Environment Characteristics and Biogeochemical Processes in the Hadal Zone

The hadal zone (e.g. trench) is characterized by its unique V-shaped geological structure, hydrodynamic environment and material and energy circulation system, has relatively higher deposition flux and burial efficiency of biogenic elements (e.g.carbon) compared with other ocean environments. As the window and channel connecting the deep biosphere and the ocean, this unique area is the tremendous trapper of marine primary production and the sink of sedimentary organic carbon, and plays a very important role in the ocean and global carbon cycling. In this paper, the advances of the formation, distribution, living environment characteristics, internal carbon cycling, potential importance in the global carbon cycling and possible responses to the global climate change of the hadal zone are reviewed, and the biogeochemical processes of biogenic nutrients influenced by the living environment in the hadal zone are mainly discussed, from the point of coupling of “physical hydrology-chemical sedimentary environment-biological activity”. And the outlook of the developing tendency in the hadal zone is summarized.