Atmospheric Input and Seasonal Inventory of Dissolved Iron in the Sargasso Sea: Implications for Iron Dynamics in Surface Waters of the Subtropical Ocean
Atmospheric Input and Seasonal Inventory of Dissolved Iron in the Sargasso Sea: Implications for Iron Dynamics in Surface Waters of the Subtropical Ocean
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DOI：
10.1029/2022gl102594
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发表时间：
2023-03
影响因子：
5.2
通讯作者：
P. Sedwick;B. Sohst;K. Buck;S. Caprara;R. Johnson;D. Ohnemus;L. E. Sofen;A. Tagliabue;B. Twining;T. Williams
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文献类型：
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作者：
P. Sedwick;B. Sohst;K. Buck;S. Caprara;R. Johnson;D. Ohnemus;L. E. Sofen;A. Tagliabue;B. Twining;T. Williams
要确定尘埃沉降在调节表层海水中必需微量营养素铁的浓度方面所起的作用，就需要了解气溶胶中海水可溶铁的通量以及真光层中溶解铁（DFe）的更替时间。在此，我们利用百慕大大西洋时间序列研究区域季节性解析的溶解铁数据以及2019年期间百慕大每周一次的气溶胶和雨水中铁含量的测量结果来估算这些量。由于垂直混合、初级生产和尘埃沉降的季节性变化，表层溶解铁浓度从早春的约0.2纳摩尔/升变化到晚夏的大于1纳摩尔/升，在0 - 200米上层，溶解铁存量分别从约30微摩尔/平方米到约80微摩尔/平方米不等。假设上层海洋每年的溶解铁大致处于稳定状态，根据我们的气溶胶和雨水数据，就风成输入而言，溶解铁在真光层的平均停留时间约为0.8 - 1.9年。
Constraining the role of dust deposition in regulating the concentration of the essential micronutrient iron in surface ocean waters requires knowledge of the flux of seawater‐soluble iron in aerosols and the replacement time of dissolved iron (DFe) in the euphotic zone. Here we estimate these quantities using seasonally resolved DFe data from the Bermuda Atlantic Time‐series Study region and weekly‐scale measurements of iron in aerosols and rain from Bermuda during 2019. In response to seasonal changes in vertical mixing, primary production and dust deposition, surface DFe concentrations vary from ∼0.2 nM in early spring to >1 nM in late summer, with DFe inventories ranging from ∼30 to ∼80 μmol/m2, respectively, over the upper 200 m. Assuming the upper ocean approximates steady state for DFe on an annual basis, our aerosol and rainwater data require a mean euphotic‐zone residence time of ∼0.8–1.9 years for DFe with respect to aeolian input.