Fe sources and transport from the Antarctic Peninsula shelf to the southern Scotia Sea
Fe sources and transport from the Antarctic Peninsula shelf to the southern Scotia Sea
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DOI：
10.1016/j.dsr.2019.06.006
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发表时间：
2019-08-01
影响因子：
2.4
通讯作者：
Zhou, Meng
中科院分区：
文献类型：
--
作者：
Jiang, Mingshun;Measures, Christopher, I;Zhou, Meng
南极半岛（AP）陆架是斯科舍海南部上层海洋溶解铁（Fe）的重要来源。在这里，我们提出了一个为期四年（2003-2006年）的数值模拟结果，使用区域耦合物理-地球化学模型，以评估铁的来源和运输的AP货架和南部斯科舍海。该模型得到验证的一套数据来自现场调查和遥感。模型结果表明，沉积物中的AP货架和南奥克尼高原（SOP）提供的主要来源的铁在南部斯科舍海的上部500米。额外的铁输入到该地区与南极绕极流（ACC）和威德尔环流的北方肢体，深海沉积物来源，灰尘沉积和冰山。AP陆架上的铁主要来自相对较浅的内陆架上的沉积物，并直接注入到水柱中，随后被汇流的陆架流向象岛输送。非货架铁出口主要是通过夹带的陆架沃茨的ACC的南部边界锋面射流沿着北方边缘的AP货架，赫斯珀里德斯槽，和SOP货架。大约70%的现成输出发生在表面混合层以下，随后通过垂直混合重新供应到真光层，主要是在南部的秋季和冬季。出口的货架衍生的铁，然后平流下游的ACC和威德尔环流，并蔓延到南部和东部的斯科舍海。综上所述，在顶部500米处的陆架铁输出几乎满足了斯科舍海南部浮游植物光合作用的所有铁需求。斯科舍海铁浓度升高的沃茨主要限于南ACC锋以南。
The Antarctic Peninsula (AP) shelf is an important source of dissolved iron (Fe) to the upper ocean in the southern Scotia Sea, one of the most productive regions of the Southern Ocean. Here we present results from a four-year (2003-2006) numerical simulation using a regional coupled physical-biogeochemical model to assess the Fe sources and transport on the AP shelf and toward the southern Scotia Sea. The model was validated with a suite of data derived from in situ surveys and remote sensing. Model results indicate that sediments in the AP shelf and the South Orkney Plateau (SOP) provide the dominant source of Fe to the upper 500 m in the southern Scotia Sea. Additional Fe inputs to the region are associated with the Antarctic Circumpolar Current (ACC) and the northern limb of the Weddell Gyre, deep-ocean sediment sources, dust deposition, and icebergs. Fe on the AP shelf originates primarily from sediments on the relatively shallow inner shelf and is directly injected into the water column and subsequently transported toward Elephant Island by the confluent shelf currents. Off-shelf Fe export is primarily through entrainment of shelf waters by the ACC's Southern Boundary frontal jet along the northern edge of the AP shelf, the Hesperides Trough, and the SOP shelf. About 70% of the off-shelf export takes place below the surface mixed layer, and is subsequently re-supplied to the euphotic zone through vertical mixing, mainly during austral fall and winter. The exported shelf-derived Fe is then advected downstream by the ACC and Weddell Gyre and spread over the southern and eastern Scotia Seas. Taken together, shelf Fe export witin top 500 m meets nearly all of the Fe demand of phytoplankton photosynthesis in the southern Scotia Sea. Waters with elevated Fe concentrations in the Scotia Sea are largely restricted to south of the Southern ACC Front.