Cold seep nitrogen fixation and its potential relationship with sulfur cycling

作者：Qiumei Quan, Jiaxing Liu, Xiaomin Xia, Si Zhang, Zhixin Ke, Minxiao Wang, Yehui Tan · 发表于：Microbiology Spectrum · 年份：2024 · DOI：10.1128/spectrum.00536-24 · 被引用次数：11 · 研究领域：Microbial Community Ecology and Physiology、Methane Hydrates and Related Phenomena、Genomics and Phylogenetic Studies

ABSTRACT Dinitrogen (N 2 ) fixation is a crucial source of bioavailable nitrogen in carbon-dominated cold seep systems. Previous studies have shown that diazotrophy is not necessarily dependent on sulfate-dependent anaerobic oxidation of methane for energy, and diverse catabolism can fuel the high-energy-demanding process in sediments. However, it remains unclear whether diazotroph can obtain energy by sulfur oxidation in sulfur-rich cold seep water column. Here, field investigations and in situ experiments were conducted in Haima cold seep to examine the effects of diverse sources of dissolved organic matter (DOM) on N 2 fixation, specifically containing sulfur, carbon, nitrogen, and phosphorus. We found that active N 2 fixation occurred in the water column above the Haima cold seep, with the Dechloromonas genus dominating the diazotroph community as revealed by nifH gene using high-throughput sequencing. In situ experiments showed an increased rate of N 2 fixation (1.15- to 12.70-fold compared to that in control group) and a greater relative abundance of the Dechloromonas genus following enrichment with sulfur-containing organic matter. Furthermore, metagenomic assembly and binning revealed that Dechloromonas sp. carried genes related to N 2 fixation ( nifDHK ) and sulfur compound oxidation ( fccAB and soxABCXYZ ), implying that the genus potentially serves as a multifunctional mediator for N 2 fixation and sulfur cycling. Our results provide new insights regarding potentia...