THE ROLE OF THE GANGES-BRAHMAPUTRA MIXING ZONE IN SUPPLYING BARIUM AND RA-226 TO THE BAY OF BENGAL
THE ROLE OF THE GANGES-BRAHMAPUTRA MIXING ZONE IN SUPPLYING BARIUM AND RA-226 TO THE BAY OF BENGAL
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DOI：
10.1016/0016-7037(93)90287-7
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发表时间：
1993-07-01
影响因子：
5
通讯作者：
MOORE, WS
中科院分区：
文献类型：
--
作者：
CARROLL, J;FALKNER, KK;MOORE, WS
恒河-布拉马普特拉河系统作为海洋的淡水来源，在世界河流中排名第四，据信向海洋提供的沉积物比其他任何河流都多；1.5 X 10（12）公斤/年（MILLIMAN和MEADE， 1983）。钡和Ra-226通常在富含沉积物的河流流入海洋的水域中富集。因此，恒河-布拉马普特拉河很可能向海洋产生全球重要的钡和Ra-226通量。在低沉积物和淡水排放时期，在恒河-布拉马普特拉河混合带的四条主要通道内采集了钡和Ra-226的水样。数据表明，除了直接由河流提供的悬浮沉积物外，高流量期间在红树林和岛屿上沉积的河流沉积物还将钡和Ra-226解吸到海水中。从这些沉积物中释放的钡和Ra-226与直接从河流中供应的沉积物相异。对恒河-布拉马普特拉河混合带钡和Ra-226的年通量也进行了估算。钡和Ra-226的通量分别为5.3 X 10(8) mol钡/年和9.5 X 10(14) dpm镭/年。报道了该体系的第一个硅酸盐和磷酸盐混合剖面。
The Ganges-Brahmaputra river system is ranked fourth among world rivers as a source of freshwater to the oceans and is believed to supply more sediment to the ocean than any other; 1.5 X 10(12) kg/yr (MILLIMAN and MEADE, 1983). Barium and Ra-226 are typically enriched in waters where sediment-laden rivers enter the ocean. As such, the Ganges-Brahmaputra is likely to produce globally significant barium and Ra-226 fluxes to the ocean.Water samples for barium and Ra-226 were collected within four major channels of the Ganges-Brahmaputra mixing zone during a period of low sediment and freshwater discharge. The data suggest that, in addition to suspended sediments supplied directly from rivers, river sediments deposited during high discharge in mangroves and on islands are desorbing barium and Ra-226 to seawater. The release of barium and Ra-226 from these sediment deposits is out-of-phase with the direct supply of sediments from the rivers. Estimates of the annual fluxes of barium and Ra-226 from the Ganges-Brahmaputra mixing zone were also derived. The fluxes of barium and Ra-226 are 5.3 X 10(8) mol barium/yr and 9.5 X 10(14) dpm radium/yr. The first silicate and phosphate mixing profiles for this system are reported.