Global Patterns of Surface Ocean Dissolved Organic Matter Stoichiometry
Global Patterns of Surface Ocean Dissolved Organic Matter Stoichiometry
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DOI：
10.1029/2023gb007788
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发表时间：
2023-11
影响因子：
5.2
通讯作者：
Zhou Liang;R. Letscher;A. Knapp
中科院分区：
文献类型：
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作者：
Zhou Liang;R. Letscher;A. Knapp
表层海洋溶解有机物（DOM）是全球海洋中碳（C）、氮（N）和磷（P）的重要储存库，由自养和异养生物群落产生和消耗。虽然以前的工作已经描述了溶解有机碳（DOC）和氮（DON）浓度的分布，我们的理解DOC：DON：DOP化学计量在全球表层海洋一直受到限制的DOP浓度测量的可用性。在这里，我们估计平均表面海洋体积和半不稳定DOC：DON：DOP化学计量在地球化学和地理定义的区域使用新的海洋DOM浓度数据库。全球平均表层海洋体积（C：N：P = 387：26：1）和半不稳定（C：N：P = 179：20：1）DOM化学计量比高于Redfield化学计量比，半不稳定DOM化学计量比与最近汇编中报告的全球平均表层海洋颗粒有机物（C：N：P = 160：21：1）相似。DOM化学计量在不同的海洋盆地之间变化，散装DOM的C：N：P范围分别为251：17：1至638：43：1和83：15：1至414：49：1。表层海洋DOP浓度的相对变化比DOC和DON大，驱动表层海洋DOC：DON：DOP化学计量比梯度。推断的DOP的自养消耗有助于解释海洋DOM C：N：P化学计量的流域内和流域间模式，水柱反硝化和铁供应的区域模式影响有利于DOP作为有机营养物使用的生态地球化学条件。具体而言，表层海洋DOM表现出越来越多的P-贫化化学计量从东到西在太平洋和从南到北在大西洋，增加P应力和减轻铁应力的模式相一致。
Surface ocean marine dissolved organic matter (DOM) serves as an important reservoir of carbon (C), nitrogen (N), and phosphorus (P) in the global ocean, and is produced and consumed by both autotrophic and heterotrophic communities. While prior work has described distributions of dissolved organic carbon (DOC) and nitrogen (DON) concentrations, our understanding of DOC:DON:DOP stoichiometry in the global surface ocean has been limited by the availability of DOP concentration measurements. Here, we estimate mean surface ocean bulk and semi‐labile DOC:DON:DOP stoichiometry in biogeochemically and geographically defined regions using newly available marine DOM concentration databases. Global mean surface ocean bulk (C:N:P = 387:26:1) and semi‐labile (C:N:P = 179:20:1) DOM stoichiometries are higher than Redfield stoichiometry, with semi‐labile DOM stoichiometry similar to that of global mean surface ocean particulate organic matter (C:N:P = 160:21:1) reported in a recent compilation. DOM stoichiometry varies across ocean basins, ranging from 251:17:1 to 638:43:1 for bulk and 83:15:1 to 414:49:1 for semi‐labile DOM C:N:P, respectively. Surface ocean DOP concentration exhibits larger relative changes than DOC and DON, driving surface ocean gradients in DOC:DON:DOP stoichiometry. Inferred autotrophic consumption of DOP helps explain intra‐ and inter‐basin patterns of marine DOM C:N:P stoichiometry, with regional patterns of water column denitrification and iron supply influencing the biogeochemical conditions favoring DOP use as an organic nutrient. Specifically, surface ocean marine DOM exhibits increasingly P‐depleted stoichiometries from east to west in the Pacific and from south to north in the Atlantic, consistent with patterns of increasing P stress and alleviated iron stress.