biostudies-literatureLi ZNational Natural Science Foundation of China (National Science Foundation of China)8655https://www.ebi.ac.uk/biostudies/studies/S-EPMC12484752biostudies-literatureUnknown16(1)Mercury accumulates in the deep sea, but its ecological impact on deep-sea ecosystems remains poorly understood. We conduct an analysis of 32 sediment cores, comprising 101 layers for the study of metagenomes, and additional 41 global reference sediment metagenomes. These sediment cores are collected from two deep-sea regions: the South China Sea and Mariana Trench, followed by revealing high mercury accumulation in the South China Sea. In these metagenomes, we find that the mercury methylation genes hgcAB are abundant in marginal seas but negligible in open oceans. Genomics result indicates that some Hg-methylating microorganisms affiliated with Desulfobacterota, Spirochaetota, and Zixibacteria in the deep-sea sediments encode MttB, the sole corrinoid-dependent methyltransferase identifieNature communicationsGenomic potential for mercury biotransformation in marine sediments across marginal slope to hadal zone.PMC1248475242376149Qian HLi ZZhu YGWei THe LWang YfalseGenomic potential for mercury biotransformation in marine sediments across marginal slope to hadal zone.Mercury accumulates in the deep sea, but its ecological impact on deep-sea ecosystems remains poorly understood. We conduct an analysis of 32 sediment cores, comprising 101 layers for the study of metagenomes, and additional 41 global reference sediment metagenomes. These sediment cores are collected from two deep-sea regions: the South China Sea and Mariana Trench, followed by revealing high mercury accumulation in the South China Sea. In these metagenomes, we find that the mercury methylation genes hgcAB are abundant in marginal seas but negligible in open oceans. Genomics result indicates that some Hg-methylating microorganisms affiliated with Desulfobacterota, Spirochaetota, and Zixibacteria in the deep-sea sediments encode MttB, the sole corrinoid-dependent methyltransferase identifie2025-01-01T00:00:00Z2025 Sep2026-06-04T00:30:12.491Z2026-05-03T03:12:20.839ZS-EPMC124847524102872410.1038/s41467-025-63808-1