TY - JOUR
T1 - Vertical stratification and metabolic versatility of methanogens in Haima cold seep sediments
T2 - Alkane-fueled acetoclastic methanogenesis revealed by metagenomics and experimental verification
AU - Jiang, Lijia
AU - Liang, Zhengjiao
AU - Williams, Tom
AU - Deng, Yinan
AU - Yu, Hao
AU - Hao, Qian
AU - Cao, Jun
AU - Zhou, Hanghai
AU - Lai, Hongfei
AU - Chen, Jiawang
AU - Chen, Haixin
AU - Zhang, Chunfang
PY - 2026/5/1
Y1 - 2026/5/1
N2 - Cold seeps are hot spots for studying the biogeochemical processes mediated by methyl-coenzyme M reductase (MCR) containing archaea, yet these processes remain poorly understood. Here, we investigated the microbial communities in a 5-m-long sediment core encompassing sulfate-methane transition zone (SMTZ), collected from the Haima cold seep. We focused on distinct biogeochemical characteristics and metagenomics to study the vertical patterns of mcrA-containing archaea and their role in alkane metabolism. Background alkane analysis showed that long chain alkanes were dominant in the sediment core. Metagenomic and quantitative PCR (qPCR) analysis revealed that the abundance of mcrA gene within and below the SMTZ were substantially higher than those above the SMTZ. We recovered 21 mcrA-containing MAGs, 11 affiliated with Methanosarcinaceae. One MAG (CG1-BIN56) encoded complete key genes for all three methanogenic pathways. Functional gene profiles suggested that acetoclastic methanogenesis is the dominant pathway. Furthermore, a 10-month anaerobic enrichment with n-alkanes (C10/C16) using SMTZ (CG15: 350 cmbsf) inocula exhibited high degradation rate (C10: 94.2% ± 2.5%, C16: 66.8% ± 2.8%) accompanied by acetate accumulation. These findings suggest that acetate, as a likely intermediate associated with alkane degradation process, potentially fuels acetoclastic methanogenesis. This indicates a likely syntrophic interaction between alkane-degrading and methane-cycling microorganisms in cold seep sediments.
AB - Cold seeps are hot spots for studying the biogeochemical processes mediated by methyl-coenzyme M reductase (MCR) containing archaea, yet these processes remain poorly understood. Here, we investigated the microbial communities in a 5-m-long sediment core encompassing sulfate-methane transition zone (SMTZ), collected from the Haima cold seep. We focused on distinct biogeochemical characteristics and metagenomics to study the vertical patterns of mcrA-containing archaea and their role in alkane metabolism. Background alkane analysis showed that long chain alkanes were dominant in the sediment core. Metagenomic and quantitative PCR (qPCR) analysis revealed that the abundance of mcrA gene within and below the SMTZ were substantially higher than those above the SMTZ. We recovered 21 mcrA-containing MAGs, 11 affiliated with Methanosarcinaceae. One MAG (CG1-BIN56) encoded complete key genes for all three methanogenic pathways. Functional gene profiles suggested that acetoclastic methanogenesis is the dominant pathway. Furthermore, a 10-month anaerobic enrichment with n-alkanes (C10/C16) using SMTZ (CG15: 350 cmbsf) inocula exhibited high degradation rate (C10: 94.2% ± 2.5%, C16: 66.8% ± 2.8%) accompanied by acetate accumulation. These findings suggest that acetate, as a likely intermediate associated with alkane degradation process, potentially fuels acetoclastic methanogenesis. This indicates a likely syntrophic interaction between alkane-degrading and methane-cycling microorganisms in cold seep sediments.
KW - cold seep sediments
KW - Biogeochemical integration
KW - Acetoclastic methanogens
KW - Alkanes metabolism
KW - Syntrophic interaction
UR - https://www.scopus.com/pages/publications/105033036513
U2 - 10.1016/j.marenvres.2026.107972
DO - 10.1016/j.marenvres.2026.107972
M3 - Article
SN - 0141-1136
VL - 217
JO - Marine Environmental Research
JF - Marine Environmental Research
M1 - 107972
ER -