Shifting microbial communities perform anaerobic oxidation of methane and methanogenesis in sediments from the Shenhu area of northern south China sea during long-term incubations

Microbial communities and their associated metabolic activities, methanogenesis anaerobic oxidation of methane (AOM), are the key components carbon biocycles in continental margin sediments. The composition diversity microbial a methanic environment have been widely investigated, but identifying direct correlations between activities remains challenge. Here, we investigated shifting that performed AOM long-term incubations (the longest is up to 199 days). AOM, methanogenesis, sulfate reduction iron occurred during incubation, 16S rRNA gene sequencing showed some bacteria were maintained or even enriched incubation compared environmental samples. In contrast, archaeal was reduced, only uncultured archaea belonging phylum Bathyarchaeota after treatment with high concentration (29.38 mM), suggesting might promote enrichment. Well-known methanotrophic (ANME) not detected, SEEP-SRB1, which syntrophy ANME, decreased approximately zero incubation. abundance known methanogens, such as genera Methanococcoides Methanosarcina , increased slightly still present at low relative (<0.15%). Incubation lower (4 mM) higher content resulted greater δ 13 CO 2 accumulation, indicating may be additional electron acceptor for AOM. Based on these results, other unknown unconventional phylotypes pathways occur Thus, methanogens methanotrophs warrants further investigation.