Open AccessThe consequences of opening the Sunda Strait on the hydrography of the eastern tropical Indian Ocean
Author(s) -
Setiawan Riza Yuliratno,
Mohtadi Mahyar,
Southon John,
Groeneveld Jeroen,
Steinke Stephan,
Hebbeln Dierk
Publication year - 2015
Publication title -
paleoceanography
Language(s) - English
Resource type - Journals
eISSN - 1944-9186
pISSN - 0883-8305
DOI - 10.1002/2015pa002802
Subject(s) - oceanography , geology , hydrography , terrigenous sediment , monsoon , last glacial maximum , holocene , climatology , structural basin , geomorphology
Abstract 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 δ 18 O (δ 18 O sw ) 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 δ 18 O sw was higher than elsewhere in the eastern tropical Indian Ocean. Seawater δ 18 O 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.