Distributions of aluminum, manganese, cobalt, and lead in the western South Pacific: Interplay between the South and North Pacific
Distributions of aluminum, manganese, cobalt, and lead in the western South Pacific: Interplay between the South and North Pacific
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南太平洋西部铝、锰、钴和铅的分布：南太平洋和北太平洋之间的相互作用
DOI：
10.1016/j.gca.2022.10.022
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发表时间：
2022
影响因子：
5
通讯作者：
Sohrin Yoshiki
中科院分区：
文献类型：
--
作者：
Zheng Linjie;Minami Tomoharu;Takano Shotaro;Sohrin Yoshiki
铝（Al）、锰（Mn）、钴（Co）和铅（Pb）强烈地从海水中清除。我们报告说，每个元素都与北太平洋的海洋环流有独特的关系（Zheng et al.，2019年）。在此，我们给出了这些元素在南太平洋西部的全深度分布，其中包括沿沿着170°W（GEOTRACES GP 19）的纬向剖面。我们确定溶解（d）和总溶解（td）浓度使用过滤和未经过滤的海水紫外线处理，我们计算不稳定的颗粒（lp）浓度之间的差异td和d浓度。这和以前的研究提出了盆地尺度的分布，这使我们能够调查一阶过程，驱动铝，锰，钴，铅在太平洋的地球化学。dAl沿沿着170°W（GP 19）-160 ° W（GPc 06）从64°S到54°N的纬向剖面表明，从表层到底层，dAl浓度在40°S到10°S之间升高（最大值为6.1 nmol/kg）。然而，lpAl的最大值出现在高纬度。lpAl/tdAl比值在30°S至0°S区域最小为0.26 ± 0.12（平均值±标准差，n= 116）。基于这些结果，我们提出了一个假设，陆地上的风化有一个显着的影响铝在海洋中的分布。在热带和亚热带岛屿以及澳大利亚，强烈的风化作用形成以高岭石为主的土壤和红土。这一过程向海洋提供dAl和高岭石。高岭石的供应导致以高岭石为主的沉积物成为dAl的主要底部来源。相反，Mn和Co的强来源是北方边界附近的大陆架。溶解态Mn和dCo通过锰的还原作用从沉积物中释放出来，并被中间水循环带走。特别是，dCo在北太平洋中层水（NPIW）、赤道太平洋中层水（EqPIW）和南极中层水（AAIW）中的分布范围为23-59 pmol/kg，潜在密度异常（σθ）为27.0。这在一定程度上是由于浮游植物吸收dCo和沉降颗粒的矿化作用。南太平洋dPb浓度为10 ± 6 pmol/kg（n= 397），北太平洋为30 ± 20 pmol/kg（n= 566）。dPb的分布特征是在北太平洋副热带模态水（SMW）和中央模态水（CMW）中有一个极大值，σθ = 26。这些结果表明，铅主要是由亚洲和俄罗斯的人为气溶胶到太平洋。由于铅是不积极采取了浮游植物，铅进入模式沃茨在冬季对流，并与模式沃茨。
Aluminum (Al), manganese (Mn), cobalt (Co), and lead (Pb) are strongly scavenged from seawater. We reported that each element is uniquely related to ocean circulation in the North Pacific (Zheng et al., 2019). Herein, we present the full-depth distributions of these elements in the western South Pacific, which include meridional sections along 170°W (GEOTRACES GP19). We determined dissolved (d) and total dissolvable (td) concentrations using filtered and unfiltered seawater without UV treatment, and we calculated labile particulate (lp) concentrations as the difference between td and d concentrations. This and the previous studies present the basin scale distributions, which enable us to investigate first order processes that drive the biogeochemistry of Al, Mn, Co, and Pb in the Pacific Ocean. The meridional section of dAl along 170°W (GP19)-160°W (GPc06) from 64°S to 54°N indicates that elevated concentrations (maximum 6.1 nmol/kg) occur between 40°S and 10°S from surface to bottom. However, the maxima of lpAl occur at high latitudes. The lpAl/tdAl ratio has a minimum of 0.26 ± 0.12 (ave ± sd,n= 116) in the zone from 30°S to 0°S. Based on these results, we propose a hypothesis that weathering on land has a significant effect on the distribution of Al in the ocean. Intensive weathering on tropical and subtropical islands and Australia forms kaolinite-dominated soils and laterite. This process provides dAl and kaolinite to the ocean. The supply of kaolinite results in kaolinite-dominated sediments that become a major bottom source for dAl. In contrast, strong sources of Mn and Co are continental shelves around the northern boundary. Dissolved Mn and dCo are released from sediments by manganese reduction and carried by intermediate water circulation. In particular, dCo spreads in the North Pacific Intermediate Water (NPIW), Equatorial Pacific Intermediate Water (EqPIW), and Antarctic Intermediate Water (AAIW); 23–59 pmol/kg at a potential density anomaly (σθ) of 27.0. This is partly owing to the uptake of dCo by phytoplankton and remineralization from settling particles. The dPb concentrations are 10 ± 6 pmol/kg (n= 397) in the South Pacific and 30 ± 20 pmol/kg (n= 566) in the North Pacific. The distribution of dPb is characterized by a maximum in the Subtropical Mode Water (SMW) and Central Mode Water (CMW) with σθ∼26 in the North Pacific. These results indicate that Pb is predominantly supplied by anthropogenic aerosols from Asia and Russia to the Pacific Ocean. Because Pb is not actively taken up by phytoplankton, Pb enters mode waters during winter convection and is transported with mode waters.