P5-XIAO Xiang

Endemic microbial community of Mariana Trench sediment enriched under ultrahigh pressure

Han Wang1, Hao Leng1, Yu Zhang1,2, Huahua Jian1, Xiang Xiao1,2*

1School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China

2Institute of Oceanography, Shanghai Jiao Tong University, Shanghai, China

*Corresponding author: xoxiang@sjtu.edu.cn

Hadal trench is characterized with extremely high hydrostatic pressure and remains one of the least understood habitats on Earth. Through the investigation on the endemic trench microorganisms we would begin to decipher the biological processes therein. Here we applied ultrahigh hydrostatic pressure as the selection force to obtain the endemic microbial community from a sediment sample of the Mariana Trench at 8, 636 m water depth with defined medium under laboratory condition. We successfully cultivated the psychrophilic and hyperpiezophilic microbial communities at 123 MPa and 152 MPa, of which the overall doubling times of 2.8 and 2.5 days were observed respectively. To our knowledge, the 152 MPa pressure has exceeded the up limit of reported optimal growth-pressure (120 MPa) and highest growth-pressure (140 MPa) for pure-cultured piezophiles. Moreover, no biomass growth from our enrichments was observed under either 0.1 MPa or 50 MPa, which proves the endemic nature of these communities.

This research provides a window to elucidate the microbial ecology and the biogeochemistry in trench systems.