A mechanistic understanding of dissolved organic phosphorus (DOP) utilization, and its role in the marine P cycle, requires knowledge of DOP molecular composition. In this study, a recently developed approach coupling electrodialysis and reverse osmosis with solution ³¹P‐NMR analysis was used to examine DOP composition within a tidally dominated salt‐marsh estuary (North Inlet, South Carolina) over seasonal and tidal time frames. The isolation technique allowed for near complete recovery of the DOP pool (90% ± 13%; n = 12) with six broad compound classes quantified: phosphonates, phosphomonoesters, phosphodiesters, pyrophosphate, di‐ and tri‐phosphate nucleotides (nucleoP_α), and polyphosphate. Our results indicate that phosphomonoesters (ca. 61%) and phosphodiesters (ca. 31%) comprise the majority of the DOP pool, with relatively small contributions from pyrophosphates (ca. 4%), phosphonates (ca. 2%), nucleoP_α (ca. 1%), and polyphosphates (ca. 1%). The study found no significant differences in DOP composition or concentration between tidal stages, despite significant tidal changes in dissolved organic nitrogen (DON):DOP stoichiometry. Significant seasonal variation was observed, with higher concentrations of phosphonates, nucleoP_α, and monophosphates and lower phosphomonoester concentrations in Fall relative to all other seasons. We hypothesize that these seasonal variations reflect the balance between specific compound class seasonal production, lability, and local P demands associated with marine vs. terrestrial sources. Our results indicate that DOP composition exists at a dynamic equilibrium that is strongly conserved across diverse marine environments.

中文翻译：

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解决沿海河口中海洋溶解的有机磷（DOP）成分

对溶解性有机磷（DOP）的利用及其在海洋P循环中的作用的机械理解需要了解DOP分子组成。在这项研究中，最近开发了一种将电渗析和反渗透与溶液³¹ P-NMR分析相结合的方法，用于检测潮汐主导的盐沼河口（南卡罗来纳州北入口）在季节性和潮汐时间框架内的DOP组成。允许的DOP池（90％±13％;的接近完全恢复的隔离技术Ñ = 12）具有六个宽化合物类量化：膦酸酯，磷酸单酯，磷酸二酯，焦磷酸，二和三磷酸核苷酸（nucleoP _α）和多磷酸盐。我们的研究结果表明，磷酸单酯（约61％）和磷酸二酯（约31％）包括大部分的DOP池，其中以焦磷酸盐相对小的贡献（约4％），膦酸盐（约2％），nucleoP _α（约1％）和多磷酸盐（约1％）。尽管溶解有机氮（DON）：DOP的化学计量存在显着变化，但该研究发现潮汐阶段之间DOP组成或浓度没有显着差异。观察显著季节变化，具有较高浓度的膦酸盐，nucleoP _α以及相对于所有其他季节而言，秋季的单磷酸盐和较低的磷酸单酯浓度。我们假设这些季节变化反映了特定化合物类别的季节产量，不稳定性以及与海洋和陆地资源相关的当地磷需求之间的平衡。我们的结果表明，DOP组成存在于动态平衡中，在各种海洋环境中都强烈保留。