The consequences of opening the Sunda Strait on the hydrography of the eastern tropical Indian Ocean
The consequences of opening the Sunda Strait on the hydrography of the eastern tropical Indian Ocean
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DOI：
10.1002/2015pa002802
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发表时间：
2015-10
期刊：
影响因子：
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通讯作者：
R. Setiawan;M. Mohtadi;J. Southon;J. Groeneveld;S. Steinke;D. Hebbeln
中科院分区：
文献类型：
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作者：
R. Setiawan;M. Mohtadi;J. Southon;J. Groeneveld;S. Steinke;D. Hebbeln
相对新鲜的爪哇海水通过巽他海峡的平流是目前热带印度洋东部盐度低至32‰的低盐度“舌”的原因。自末次冰期以来，巽他大陆架暴露出来，通过巽他海峡的任何平流都被切断，热带印度洋东部水文条件的演变以及巽他海峡开放对这些条件的影响程度尚不清楚。在这里，我们分析了两个沉积物芯（GeoB 10042-1和GeoB 10043-3）收集自热带印度洋东部的巽他海峡，涵盖了过去的约40,000年。我们调查了与海平面驱动的巽他海峡开放相关的陆源供应、海表温度（SST）和海水δ 18 O（δ 18 Osw）变化的幅度。我们在巽他海峡的新拼接记录表明，在末次冰期，平均SST较冷，δ 18 Osw高于热带印度洋东部的其他地方。巽他海峡开放后，海水δ 18 O下降约0.5‰，SST上升约1.7°C。我们认为，新鲜的海面条件一直持续到现在，由于低盐度的爪哇海水通过巽他海峡，另外增加了海洋生产力，通过同时增加陆源供应的热带印度洋东部的持续运输。
The advection of relatively fresh Java Sea water through the Sunda Strait is presently responsible for the low-salinity “tongue” in the eastern tropical Indian Ocean with salinities as low as 32‰. The evolution of the hydrologic conditions in the eastern tropical Indian Ocean since the last glacial period, when the Sunda shelf was exposed and any advection via the Sunda Strait was cutoff, and the degree to which these conditions were affected by the Sunda Strait opening are not known. Here we have analyzed two sediment cores (GeoB 10042–1 and GeoB 10043–3) collected from the eastern tropical Indian Ocean off the Sunda Strait that cover the past ~40,000 years. We investigate the magnitude of terrigenous supply, sea surface temperature (SST), and seawater δ18O (δ18Osw) changes related to the sea level-driven opening of the Sunda Strait. Our new spliced records off the Sunda Strait show that during the last glacial, average SST was cooler and δ18Osw was higher than elsewhere in the eastern tropical Indian Ocean. Seawater δ18O decreased ~0.5‰ after the opening of the Sunda Strait at ~10 kyr B.P. accompanied by an SST increase of 1.7°C. We suggest that fresher sea surface conditions have persisted ever since due to a continuous transport of low-salinity Java Sea water into the eastern tropical Indian Ocean via the Sunda Strait that additionally increased marine productivity through the concomitant increase in terrigenous supply.