Abstract:

Nitrification, the two-step oxidation of ammonia to nitrate via nitrite, plays a critical role in the global carbon cycle by fixing CO2 with the form of chemolithoautotrophy, and consequently influencing the organic carbon pool and food web structure in the dark ocean. It has long been assumed that the first and rate-limiting step of nitrification, ammonia oxidation, was restricted to a few groups within the domain Bacteria. However, the recent discovery of ammonia-oxidizing archaea (AOA) has seriously challenged our understanding of the microbial ecology and biogeochemistry of nitrification in the ocean. Therefore, the biogeochemical mechanism of CO2 fixation by microbial nitrification is largely unknown. The multi-disciplinary studies in this field have expanded and
strengthened the existing oceanographic carbon-nitrogen network, and increased our understanding on microbial and biogeochemical process of autotrophic production by marine nitrification. In this paper we reviewed the progress of microbial nitrification and chemolithpautotrophy carbon fixation in the deep sea, which would offer a reference for the researchers in this field.