Distinct iron cycling in a Southern Ocean eddy
Distinct iron cycling in a Southern Ocean eddy
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DOI：
10.1038/s41467-020-14464-0
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发表时间：
2020-02-11
影响因子：
16.6
通讯作者：
Boyd, Philip W.
中科院分区：
文献类型：
--
作者：
Ellwood, Michael J.;Strzepek, Robert F.;Boyd, Philip W.
中尺度涡旋在含铁有限的南大洋中普遍存在，控制着海洋-大气交换过程，但其对浮游植物生产力的影响尚不清楚。在这里，我们探讨了铁（Fe）在冷心涡旋的地球化学循环。在涡流表面溶解铁（dFe）浓度和浮游植物生产力相对于外部沃茨是非常低的。在涡流浮游植物铁碳吸收比升高2-6倍，表明上调细胞内铁收购导致dFe停留时间类似于1天。重dFe同位素值进行了测量，在涡流表面沃茨突出广泛的dFe细胞贩运。在透光层以下，dFe同位素值较轻，与回收的营养物质和细胞丰度的峰值一致，表明微生物介导的Fe循环增强。我们的测量结果表明，南大洋涡旋的孤立性质可以产生明显不同的铁的地球化学相比，周围的沃茨与细胞上调铁的吸收和利用循环过程来维持自己。
Mesoscale eddies are ubiquitous in the iron-limited Southern Ocean, controlling ocean-atmosphere exchange processes, however their influence on phytoplankton productivity remains unknown. Here we probed the biogeochemical cycling of iron (Fe) in a cold-core eddy. In-eddy surface dissolved Fe (dFe) concentrations and phytoplankton productivity were exceedingly low relative to external waters. In-eddy phytoplankton Fe-to-carbon uptake ratios were elevated 2-6 fold, indicating upregulated intracellular Fe acquisition resulting in a dFe residence time of similar to 1 day. Heavy dFe isotope values were measured for in-eddy surface waters highlighting extensive trafficking of dFe by cells. Below the euphotic zone, dFe isotope values were lighter and coincident with peaks in recycled nutrients and cell abundance, indicating enhanced microbially-mediated Fe recycling. Our measurements show that the isolated nature of Southern Ocean eddies can produce distinctly different Fe biogeochemistry compared to surrounding waters with cells upregulating iron uptake and using recycling processes to sustain themselves.