资源环境科技发展态势分析平台

Geological sources of methane (CH₄), such as hydrocarbon seeps, are significant yet poorly constrained sources of CH₄ to seawater and the overlying atmosphere_. We investigate the radiocarbon content (¹⁴C) and concentrations of dissolved CH₄ in surface waters from the Coal Oil Point seep field to test the hypothesis that geological sources can dominate the regional background signal of CH₄. We find that surface waters with elevated CH₄ concentration were populated with seep‐CH₄ and that lower concentrations of CH₄ were well explained by mixing with the regional background of non‐geological CH₄. Substantial differences in concentration and ¹⁴C‐CH₄ were observed over distances <5 km, demonstrating that surface currents mix background‐CH₄ into the seep field. These results indicate that even a prolific seep region like the Santa Barbara Basin exerts limited influence on the regional background of CH₄ in the surface layer but is a significant driver of patchiness in oceanic CH₄ biogeochemistry.