Behavior of dissolved redox sensitive elements (U, Mo and Re) in the water column of the Bay of Bengal
Behavior of dissolved redox sensitive elements (U, Mo and Re) in the water column of the Bay of Bengal
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DOI：
10.1016/j.marchem.2011.04.001
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发表时间：
2011-09
期刊：
影响因子：
3
通讯作者：
S. Singh;S. Singh;R. Bhushan
中科院分区：
文献类型：
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作者：
S. Singh;S. Singh;R. Bhushan
本文测定了孟加拉湾（BoB）水体中氧化还原敏感元素U、Mo和Re的溶解浓度，以跟踪其在中间深度亚氧层中的分布和行为。在~11°N以北的中间沃茨（200- 800 m）中，溶解氧含量降低到~3μmol/L。沿沿着87°E断面的表层沃茨中U、Mo和Re的分布呈现出南北梯度，并与盐度显著相关，这突出表明恒河-雅鲁藏布江（G-B）河流在控制这三种元素的地球化学收支方面的主导影响。这三种元素的浓度在表层和深层沃茨的鲍勃是由盐度暗示他们的保守行为。在宏观尺度上，没有明显的去除U，Mo，或Re的亚氧层中的BoB水柱，与其他海洋区域的亚氧区的早期研究相一致。此外，它们在海湾中的保守行为表明，G-B和其他河流每年输送约109吨富含有机物的悬浮物对确定其分布没有任何可测量的影响。这项研究表明，在孟加拉湾的水柱中普遍存在的亚氧条件和高颗粒通量不影响U，Mo和Re的保守行为。溶解的Re浓度在上层的中央BoB似乎是略高于预期的基础上，其盐度。这似乎是戈达瓦里河的贡献，戈达瓦里河流入鲍勃河，溶解的Re比海水高三倍。在孟加拉湾中部较高的Re浓度表明，混合过程中的本地环流和/或涡的BoB运输河流溶解的物质到离岸约400公里。需要从戈达瓦里海岸到中央海湾的更详细的Re断面来证实这一点。
The dissolved concentrations of redox sensitive elements, U, Mo and Re have been measured in the water column of the Bay of Bengal (BoB) to track their distributions and behavior in its suboxic layers at the intermediate depths. The dissolved oxygen content in the intermediate waters (200–800m) north of ~11°N decreases to values as low as ~3μmol/ℓ. The distribution of U, Mo and Re in the surface waters along the 87°E transect shows a north–south gradient with significant correlation with salinity, underscoring the dominant influence of the Ganga–Brahmaputra (G–B) Rivers in controlling the geochemical budgets of these three elements. The concentrations of these three elements in surface and deep waters of the BoB are governed by salinity suggestive of their conservative behavior. On a macroscale, there is no discernable removal of U, Mo, or Re from the suboxic layer in the BoB water column, consistent with earlier studies in the suboxic zones of other oceanic regions. Further, their conservative behavior in the bay, suggest that the annual delivery of ~109tons of suspended matter rich in organic matter by G–B and other rivers do not have any measurable impact in determining their distributions. This study suggests that the suboxic conditions and high particulate flux prevailing in the water column of the Bay of Bengal do not affect the conservative behavior of U, Mo and Re. The dissolved Re concentrations in the upper layers in the central BoB seem to be marginally higher compared to that expected based on their salinities. This seems to be contributed from the Godavari River, which drains into the BoB and has dissolved Re three times higher than seawater. The higher Re concentrations in the central Bay of Bengal suggest that mixing process by local gyre and/or eddies in the BoB transports riverine dissolved material to ~400km offshore. More detailed transects of Re from the Godavari coast to central bay are needed to confirm this.