Past summer upwelling events in the Gulf of Oman derived from a coral geochemical record

• Watanabe, Takaaki K.

• Watanabe, Tsuyoshi

• Yamazaki, Atsuko

• Pfeiffer, Miriam

• Garbe-Schoenberg, Dieter

• Claereboudt, Michel R.

Abstract

We used a high-resolution oxygen isotope (delta O-18(coral)), carbon isotope (delta O-18(coral)) and Sr/Ca ratios measured in the skeleton of a reef-building coral, Porites sp., to reveal seasonal-scale upwelling events and their interannual variability in the Gulf of Oman. Our delta C-13(coral) record shows sharp negative excursions in the summer, which correlate with known upwelling events. Using delta C-13(coral) anomalies as a proxy for upwelling, we found 17 summer upwelling events occurred in the last 26 years. These anomalous negative excursions of delta C-13(coral) result from upwelled water depleted in C-13 (dissolved inorganic carbon) and decreased water-column transparency. We reconstructed biweekly SSTs from coral Sr/Ca ratios and the oxygen isotopic composition of seawater (delta O-18(SW)) by subtracting the reconstructed Sr/Ca-SST from delta O-18(coral). Significant delta O-18(SW) anomalies occur during major upwelling events. Our results suggest delta C-13(coral) anomalies can be used as a proxy for seasonal upwelling intensity in the Gulf of Oman, which, driven by the Indian/Arabian Summer Monsoon, is subject to interannual variability.

Journal

• Scientific reports

  Scientific reports 7 4568-, 2017-07-04

  Nature Publishing Group

Details

• CRID: 1050282677904152576
• NII Article ID: 120006454490
• HANDLE: 2115/68836
• ISSN: 20452322
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • CiNii Articles