Autotrophic ammonia oxidation in a deep-sea hydrothermal plume
發佈日期：2016-09-22
- 標題
- Autotrophic ammonia oxidation in a deep-sea hydrothermal plume
- 作者
- Phyllis Lam, James P Cowen, Ronald D Jones
- 文件屬性
- 國外期刊
- 知識分類
- 基礎研究
- 出版年
- 2004
- 刊名
- FEMS Microbiology Ecology
- 關鍵字
- Ammonia oxidation; Chemolithoautotrophy; In situ organic carbon production; Hydrothermal plume; Fluorescence in situ hybridization; Endeavour; Mid-ocean ridge; Nitrification; Marine nitrogen cycling
- 點閱數
- 3163
摘要
Direct evidence for autotrophic ammonia oxidation is documented for the first time in a deep-sea hydrothermal plume. Elevated NH4+ concentrations of up to 341±136 nM were recorded in the plume core at Main Endeavour Field, Juan de Fuca Ridge. This fueled autotrophic ammonia oxidation rates as high as 91 nM day−1, or 92% of the total net NH4+ removal. High abundance of ammonia-oxidizing bacteria was detected using fluorescence in situ hybridization. Ammonia-oxidizing bacteria within the plume core (1.0–1.4×104 cells ml−1) accounted for 7.0–7.5% of the total microbial community, and were at least as abundant as methanotrophs. Ammonia-oxidizing bacteria were a substantial component of the particle-associated communities (up to 51%), with a predominance of the r-strategist Nitrosomonas-like cells. In situ chemolithoautotrophic organic carbon production via ammonia oxidation may yield 3.9–18 mg C m−2 day−1within the plume directly over Main Endeavour Field. This rate was comparable to that determined for methane oxidation in a previous study, or at least four-fold greater than the flux of photosynthetic carbon reaching plume depths measured in another study. Hence, autotrophic ammonia oxidation in the neutrally buoyant hydrothermal plume is significant to both carbon and nitrogen cycling in the deep-sea water column at Endeavour, and represents another important link between seafloor hydrothermal systems and deep-sea biogeochemistry.