Nutrient budgets in the subtropical ocean gyres dominated by lateral transport
Nutrient budgets in the subtropical ocean gyres dominated by lateral transport
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DOI：
10.1038/ngeo2812
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发表时间：
2016-11-01
影响因子：
18.3
通讯作者：
Moore, J. Keith
中科院分区：
文献类型：
--
作者：
Letscher, Robert T.;Primeau, Francois;Moore, J. Keith
海洋环流补充因生物生产和出口而耗尽的表层养分。人们认为垂直过程占主导地位，但估计的垂直营养通量不足以解释观测到的副热带海洋环流净生产力(1)。横向输入有助于平衡北大西洋的营养预算(2-7)，但它们对其他环流的重要性尚未得到证明。在这里，我们使用耦合循环和生态系统动力学的海洋模型来表明，来自环流边缘的无机和有机形式的氮和磷的横向运输和生物吸收超过了营养物的垂直输送，提供了关闭环流养分预算所需的24-36%的氮和44-67%的磷。在百慕大和夏威夷的时间序列站点，近一半的横向运输年度横向供应发生在夏季至秋季分层期间，有助于解释无机碳减少和固氮的季节性模式。我们的研究证实了上层海洋横向养分输送对于了解海洋最大生物群落中碳和养分的生物循环的重要性。
Ocean circulation replenishes surface nutrients depleted by biological production and export. Vertical processes are thought to dominate, but estimated vertical nutrient fluxes are insufficient to explain observed net productivity in the subtropical ocean gyres(1). Lateral inputs help balance the North Atlantic nutrient budget(2-7), but their importance for other gyres has not been demonstrated. Here we use an ocean model that couples circulation and ecosystem dynamics to show that lateral transport and biological uptake of inorganic and organic forms of nitrogen and phosphorus from the gyre margins exceeds the vertical delivery of nutrients, supplying 24-36% of the nitrogen and 44-67% of the phosphorus required to close gyre nutrient budgets. At the Bermuda and Hawaii time-series sites, nearly half of the annual lateral supply by lateral transport occurs during the summer-to-fall stratified period, helping explain seasonal patterns of inorganic carbon drawdown and nitrogen fixation. Our study confirms the importance of upper-ocean lateral nutrient transport for understanding the biological cycles of carbon and nutrients in the ocean's largest biome.