In oligotrophic ocean regions, dissolved organic phosphorus (DOP) plays a prominent role as a source of phosphorus (P) to microorganisms. An important bioavailable component of DOP is phosphonates, organophosphorus compounds with a carbon‐phosphorus (C‐P) bond, which are ubiquitous in high molecular weight dissolved organic matter (HMWDOM). In addition to being a source of P, the degradation of phosphonates by the bacterial C‐P lyase enzymatic pathway causes the release of trace hydrocarbon gases relevant to climate and atmospheric chemistry. In this study, we investigated the roles of phosphate and phosphonate cycling in the production of methane (CH₄) and ethylene (C₂H₄) in the western North Atlantic Ocean, a region that features a transition in phosphate concentrations from coastal to open ocean waters. We observed an inverse relationship between phosphate and the saturation state of CH₄ and C₂H₄ in the water column, and between phosphate and the relative abundance of the C‐P lyase marker gene phnJ. In phosphate‐depleted waters, methylphosphonate and 2‐hydroxyethylphosphonate, the C‐P lyase substrates that yield CH₄ and C₂H₄, respectively, were readily degraded in proportions consistent with their abundance and bioavailability in HMWDOM and with the concentrations of CH₄ and C₂H₄ in the water column. We conclude that phosphonate degradation through the C‐P lyase pathway is an important source and a common production pathway of CH₄ and C₂H₄ in the phosphate‐depleted surface waters of the western North Atlantic Ocean and that phosphate concentration can be an important control on the saturation state of these gases in the upper ocean.

中文翻译：

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磷酸盐循环支持在贫磷酸盐的北大西洋西部甲烷和乙烯的过饱和

在贫营养海洋地区，溶解性有机磷（DOP）作为微生物的磷（P）来源发挥着重要作用。DOP的重要生物利用成分是膦酸酯，具有碳-磷（C-P）键的有机磷化合物，在高分子量溶解有机物（HMWDOM）中普遍存在。除磷的来源外，细菌C-P裂解酶的酶促途径对膦酸酯的降解还导致释放与气候和大气化学有关的痕量烃类气体。在这项研究中，我们调查了磷酸盐和膦酸酯循环在甲烷（CH ₄）和乙烯（C ₂ H _{4）生产中的作用}）位于北大西洋西部，该地区的磷酸盐浓度从沿海水域向开放海域过渡。我们观察到磷酸盐与水柱中CH ₄和C ₂ H ₄的饱和状态之间以及磷酸盐与C-P裂解酶标记基因phnJ的相对丰度之间呈反比关系。在磷酸盐贫化的水中，甲基膦酸酯和2-羟乙基膦酸酯，分别产生CH ₄和C ₂ H ₄的C-P裂解酶底物易于降解，其比例与其在HMWDOM中的丰度和生物利用度以及CH ₄的浓度一致和C ₂水柱中的H ₄。我们得出的结论是，在北大西洋西部缺磷的地表水中，通过C-P裂解酶途径降解的膦酸酯是CH ₄和C ₂ H ₄的重要来源和常见生产途径，磷酸盐浓度可能是重要的控制这些气体在上层海洋中的饱和状态。