The oceans are natural sources of atmospheric methane (CH₄), but the origin of excess CH₄ at the surface remains enigmatic. Incubation experiments were conducted in the western North Pacific (WNP) and its marginal seas (i.e., Yellow Sea and South China Sea [SCS]) to identify the degradation of methylphosphonate (MPn) to CH₄ in the oceans and the microbes associated with MPn‐driven CH₄ production. In the coastal seawater of the Yellow Sea, CH₄ was observed to accumulate after MPn enrichment with a high MPn to CH₄ conversion efficiency (approximately 60%). Dissolved inorganic phosphorus (Pi) did not effectively restrict the microbial utilization of MPn in the eutrophic coastal waters. The results of 16S rRNA gene sequencing showed that Vibrio spp. were the dominant bacteria in the MPn‐amended treatments. Moreover, several Vibrio isolates isolated from the coastal waters were found to produce CH₄ while growing in culture using MPn as the sole P source, thereby indicating that Vibrio spp. might be the major contributors to MPn‐dependent CH₄ production. In oligotrophic areas, such as the SCS and WNP, CH₄ production from MPn metabolism was also observed in the surface seawater. In contrast to coastal waters, this pathway in oligotrophic areas is regulated by dissolved Pi availability. This work confirms that aerobic CH₄ formation from MPn degradation can occur both in eutrophic coastal waters and oligotrophic oceans driven by MPn‐utilizing microorganisms (especially heterotrophic bacteria), which may have a significant impact on our understanding of the CH₄ and P cycles in global oceans.

中文翻译：

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北太平洋西部及其边缘海含氧海水中的甲烷生产

海洋是大气中甲烷（CH ₄）的自然来源，但表面上过量的CH ₄的来源仍然令人费解。在北太平洋西部及其边缘海（即黄海和南海[SCS]）进行了温育实验，以鉴定海洋中的甲基膦酸酯（MPn）降解为CH ₄以及与MPn相关的微生物驱动的CH ₄生产。在黄海的沿海海水中，观察到CH ₄在富含MPn的MPn富集后富集到CH ₄转换效率（大约60％）。溶解的无机磷（Pi）不能有效地限制富营养化沿海水域中MPn的微生物利用。16S rRNA基因测序的结果表明弧菌属。是MPn改良疗法中的优势细菌。此外，发现从沿海水域分离出的几种弧菌分离株在以MPn作为唯一P源的培养条件下生长时会产生CH ₄，从而表明弧菌属。可能是依赖MPn的CH ₄生产的主要贡献者。在SCS和WNP等贫营养区，CH ₄在表层海水中也观察到了MPn代谢产生的产物。与沿海水域相比，贫营养区的这种途径受溶解的Pi可用性的调节。这项工作证实，有氧CH ₄从MPN降解形成可以通过MPN-利用微生物（尤其是异养细菌）驱动富营养化沿海水域和贫营养海洋发生二者，这可能对我们的CH的理解显著冲击₄中和P个周期全球海洋。