Evidence for production and lateral transport of dissolved organic phosphorus in the eastern subtropical North Atlantic
Evidence for production and lateral transport of dissolved organic phosphorus in the eastern subtropical North Atlantic
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DOI：
10.1002/2013gb004801
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发表时间：
2014-08
影响因子：
5.2
通讯作者：
S. Reynolds;C. Mahaffey;V. Roussenov;Richard G. Williams
中科院分区：
文献类型：
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作者：
S. Reynolds;C. Mahaffey;V. Roussenov;Richard G. Williams
与其他海洋盆地相比，北大西洋副热带地区的磷酸盐和溶解有机磷（DOP）浓度长期偏低，限制了浮游植物的生长。磷酸盐和DOP从环流的生产侧翼运输到其内部被假设为一个重要的磷供应途径。2011年春季，在东大西洋的一次航行中，研究人员测量了西北非洲大陆架地区、亚热带和热带地区磷酸吸收速率、碱性磷酸酶活性（APA）和DOP产量。陆架地区的DOP生产速率（43±41 nM d - 1）是亚热带地区（6.9±4.4 nM d - 1）的6倍。相比之下，亚热带地区的APA（8.0±7.3 nM d - 1）是陆架地区的三倍，表明相对于陆架地区（2.6±2.1 nM d - 1）， dopp的利用率更高。因此，观测结果表明陆架区域的DOP净生产和环流内部的DOP净消耗或DOP生产和消耗接近平衡。允许涡旋的模式实验表明：(i) DOP占地表水总磷的一半以上，（ii） DOP通过环流和涡旋环流的组合从陆架区域向西输送，以及（iii）平流DOP在大部分副热带环流中支持高达70%的颗粒输出。我们的观测和模拟相结合的研究支持了陆架区DOP的水平输送是向副热带北大西洋表层供应磷的重要机制的观点。
The concentration of phosphate and dissolved organic phosphorus (DOP) is chronically low and limits phytoplankton growth in the subtropical North Atlantic relative to other ocean basins. Transport of phosphate and DOP from the productive flanks of the gyre to its interior has been hypothesized as an important phosphorus supply pathway. During a cruise in the eastern Atlantic in spring 2011, the rates of phosphate uptake, alkaline phosphatase activity (APA), and DOP production were measured in the northwest African shelf region, subtropics, and tropics. Rates of DOP production were sixfold higher in the shelf region (43 ± 41 nM d−1) relative to the subtropics (6.9 ± 4.4 nM d−1). In contrast, APA was threefold higher in the subtropics (8.0 ± 7.3 nM d−1), indicative of enhanced DOP utilization, relative to the shelf region (2.6 ± 2.1 nM d−1). Hence, observations suggest net production of DOP in the shelf region and either net consumption of DOP or a near balance in DOP production and consumption in the gyre interior. Eddy‐permitting model experiments demonstrate that (i) DOP accounts for over half the total phosphorus in surface waters, (ii) DOP is transported westward from the shelf region by a combination of gyre and eddy circulations, and (iii) advected DOP supports up to 70% of the particle export over much of the subtropical gyre. Our combined observational and modeling study supports the view that the horizontal transport of DOP from the shelf region is an important mechanism supplying phosphorus to the surface subtropical North Atlantic.