Horizontal and vertical heterogeneity of sediment microbial community in Site F cold seep, the South China Sea

Site F is the most vigorous cold seep known on continental slope of northern South China Sea. Up to now, microbial community structures in sediments based high-throughput sequencing 16S rRNA genes have been studied extensively. However, few studies investigated at fine vertical scales and control stations outside F. In this study, a comprehensive investigation communities along depths varying from 0 24 cm below sea floor (cmbsf) four sampling sites—SRS (Southern Reduced Sediment), NRS (Northern Control 1 (close F), 2 (far F)—was carried out. The high relative abundances anaerobic methanotrophic archaea (ANME), Desulfobacterota [sulfate-reducing bacteria (SRB)], Campylobacteria [sulfur-oxidizing (SOB)] SRS indicated that these two sites were newborn compared with non-seep sites, 1, 2. A positive correlation between ANME-1b, ANME-2, SEEP-SRB an enrichment Sulfurovum Methlomonadaceae found surface both NRS, indicating processes oxidation methane (AOM), sulfur oxidation, sulfate reduction might occur sites. was enriched ANME-1b SEEP-SRB2 proposed sulfate-methane transition zone (SMTZ) approximately located 8 cmbsf. abundance ANME may due concentration methane. Desulfatiglans , Methanosarcinaceae SMTZ about 10 According analyses structure environmental factors, could be described as notable reduced sediment site low H S nourished abundant SEEP-SRB1, Methanosarcinales which showed similar distribution pattern. Our study expands current knowledge differences sheds light horizontal heterogeneity