Iron and nutrient dynamics along the East Kamchatka current, western Bering sea basin and Gulf of Anadyr
Iron and nutrient dynamics along the East Kamchatka current, western Bering sea basin and Gulf of Anadyr
复制标题
东堪察加海流、西白令海盆地和阿纳德尔湾沿线的铁和营养动态
DOI：
10.1016/j.pocean.2021.102662
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发表时间：
2021
影响因子：
4.1
通讯作者：
Yasuda I
中科院分区：
文献类型：
--
作者：
Nishioka J;Hirawake T;Nomura D;Yamashita Y;Ono K;Murayama A;Shcherbinin A;Volkov Y N;Mitsudera H;Ebuch N;Wakatsuchi M;Yasuda I
分析了2014年和2018年夏季白令海西部东堪察加海流（EKC）观测到的铁（Fe）和营养盐数据，包括堪察加盆地、东北陆架斜坡和阿纳迪尔湾。结果表明，高营养和低叶绿素水（铁有限的亚北极太平洋水），扩展到EKC区域的边缘的位置。铁的供应与来自堪察加半岛的淡水供应有关，并导致了EKC内堪察加半岛沿岸的营养盐耗竭。与亚北极太平洋相一致，堪察加海盆的中间层（26.6-27.6 σθ）存在着一个广泛的密度范围内的极高浓度的硝酸盐（N）和磷酸盐（P）和极低浓度的溶解氧，并形成了一个中间营养库。而溶解态Fe（dFe）和碳酸盐（Si）的浓度均在27.6 σθ等密度面以下的深层最高，表明在盆地中层水中dFe和Si循环与N和P循环是解耦的。dFe浓度随深度的增加，在深层可能是由于减少颗粒铁发生在底栖孔隙水的斜坡上或在沉降颗粒微环境，如负N* 指数。根据2018年夏季堪察加海峡和EKC附近的观测资料，堪察加半岛半岛太平洋一侧EKC中间层水的化学性质主要受从阿留申群岛东南部流出的西亚北极环流的影响，堪察加盆地的水流经堪察加海峡的EKC沿海一侧的影响较小。我们的研究结果还表明，富营养水入侵发生从阿留申盆地中间营养池的底层的阿纳迪尔湾。此外，硝酸盐的去除通过反硝化过程和沉积铁的输入发生在入侵的底层水。研究结果对了解亚北极太平洋、白令海和北冰洋之间的海洋地球化学相互作用具有重要意义。
Analysis of observed iron (Fe) and nutrient data from the East Kamchatka Current (EKC) in the western Bering Sea, including the Kamchatka Basin, northeastern shelf slope, and Gulf of Anadyr, in the summers of 2014 and 2018 was conducted. The results indicate the location of the edge of high-nutrient and low-chlorophyll water (Fe-limited subarctic Pacific water), which expands into the EKC area. The supply of Fe was related to the freshwater supply from the Kamchatka Peninsula and caused nutrient depletion along the coast of the Kamchatka Peninsula in the EKC. Consistent with the subarctic Pacific, water with extremely high nitrate (N) and phosphate (P) concentrations and extremely low dissolved oxygen concentrations was observed in a wide density range in the intermediate layer (26.6–27.6 σθ) in the Kamchatka Basin and formed an intermediate nutrient pool. However, the concentrations of both dissolved Fe (dFe) and silicic acid (Si) were highest in the deep layer below the 27.6 σθisopycnal surface in the basin, indicating that the dFe and Si cycles were decoupled from the N and P cycle in the basin intermediate water. The increase in dFe concentration with depth in the deep layer was probably due to a reduction in particulate Fe that occurred in the benthic pore water on the slope or in the settling particulate microenvironment, as indicated by a negative N* index. Based on the observed data around the Kamchatka Strait and EKC in the summer of 2018, the chemical properties of the water in the intermediate layers in the EKC on the Pacific side of the Kamchatka Peninsula were mainly influenced by circulation of the Western Subarctic Gyre, which flows from the southeastern Aleutian Islands, with minor influence from Kamchatka Basin water flowing through the Kamchatka Strait on the coastal side of the EKC. Our results also indicate that nutrient-rich water intrusion occurred from the Aleutian Basin intermediate nutrient pool to the bottom layer of the Gulf of Anadyr. Additionally, nitrate removal by via the denitrification process and the input of sedimentary Fe occurred in the intruding bottom water. The findings from this study are important for understanding the biogeochemical interactions occurring among the subarctic Pacific, Bering Sea, and Arctic Ocean.