Impact of atmospheric deposition on the contrasting iron biogeochemistry of the North and South Atlantic Ocean
Impact of atmospheric deposition on the contrasting iron biogeochemistry of the North and South Atlantic Ocean
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DOI：
10.1002/gbc.20056
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发表时间：
2013-12
影响因子：
5.2
通讯作者：
S. Ussher;E. Achterberg;Claire F. Powell;A. Baker;T. Jickells;R. Torres;P. Worsfold
中科院分区：
文献类型：
--
作者：
S. Ussher;E. Achterberg;Claire F. Powell;A. Baker;T. Jickells;R. Torres;P. Worsfold
测定了大西洋两个经向横断面上部水柱中溶解铁 (dFe) 的分布以及 dFe 的大气和垂直俯冲通量。这些数据证明了北大西洋和南大西洋铁生物地球化学之间的差异，并显示了地理省份之间地表水中分馏铁物种尺寸的明确梯度。最高的 dFe 和最低的混合层停留时间（0.4-2.5 年）出现在北部热带和亚热带地区。相比之下，南大西洋环流的 dFe 浓度较低（5 年），这可能是由于该地区大气输入较低且铁的生物循环效率较高。在北大西洋和热带省份，dFe 向地表水的垂直输入通量范围为 20 至 170 nmol m-2 d-1，而南大西洋的平均通量估计为 6-13 nmol m-2 d-1。我们的估计表明，大西洋表面的 dFe 分布变化（地表水总垂直 Fe 通量的 50%），而不是上升流或垂直混合。这证明了陆地来源的大气铁通量与大西洋碳和氮的生物循环之间的紧密联系。
Dissolved iron (dFe) distributions and atmospheric and vertical subduction fluxes of dFe were determined in the upper water column for two meridional transects of the Atlantic Ocean. The data demonstrate the disparity between the iron biogeochemistry of the North and South Atlantic Ocean and show well‐defined gradients of size fractionated iron species in surface waters between geographic provinces. The highest dFe and lowest mixed layer residence times (0.4–2.5 years) were found in the northern tropical and subtropical regions. In contrast, the South Atlantic Gyre had lower dFe concentrations (5 years), presumably due to lower atmospheric inputs and more efficient biological recycling of iron in this region. Vertical input fluxes of dFe to surface waters ranged from 20 to 170 nmol m–2 d–1 in the North Atlantic and tropical provinces, whereas average fluxes of 6–13 nmol m–2 d–1 were estimated for the South Atlantic. Our estimates showed that the variable dFe distribution over the surface Atlantic (50% of total vertical Fe flux to surface waters) rather than upwelling or vertical mixing. This demonstrates the strength of the connection between land‐derived atmospheric Fe fluxes and the biological cycling of carbon and nitrogen in the Atlantic Ocean.