Geochemical and microbial controls on methane distribution in coastal sediments: A case study from the Bohai and South Yellow Seas, China

CH₄ is among the most potent greenhouse gases. In this study, we investigated one of the important CH₄ production hotspots, the continental margins. We examined the spatiotemporal distributions of CH₄ in sediment cores from the Bohai and South Yellow Seas, China. Using real-time PCR and metagenomic sequencing, we analyzed the microbial communities related to CH₄ production. Our results indicated that concentrations of CH₄ generally increased with depth gradually, minimal seasonal variation observed between spring and summer. Notably, spatial heterogeneity, rather than temporal variation, was the predominant factor affecting CH₄ distribution and methanogen community differences in sediments. Furthermore, the structure of microbial communities, in conjunction with environmental factors, significantly impacts potential CH₄ production. These findings provide valuable insights into the mechanisms underlying methane production and its environmental controls in marine sediments.