Stable oxygen isotope records of corals and a sclerosponge in the Western Pacific warm pool
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High-resolution measurements of the stable oxygen isotopic signature (δ18O) of two new 10-year Porites lobata coral cores and one previously studied multi-decadal sclerosponge Acanthocheatetes wellsi from the Republic of Palau (7°16′N, 134°31′E) located in the Western Pacific warm pool were analyzed and monthly interpolated time-series records developed. Despite significant differences in collection depth and growth rates, both coral and sclerosponge faithfully recorded the interannual changes of sea surface salinity (SSS) driven by the strong influence of the El Niño Southern Oscillation (ENSO). The strong relationship of coral skeletal δ18O with SSS, but not sea surface temperature or precipitation, confirms previous findings that changes in Palau regional surface water are driven by the advection of water masses into the area over interannual timescales associated with ENSO. Opportunities exist for the expansion of short coral proxy records with longer sclerosponge records to verify the stability of ENSO-induced SSS variability over longer timescales.
KeywordsCoral δ18O Sclerosponge El Niño Southern oscillation Western Pacific warm pool Salinity
We thank the following people and organizations for their assistance: J. Bauer, M. Cathey, P. Colin, O. Gibb, D. Idip, T. Isamu, J. Kloulechad, J. Palardy, B. Linsley, A. Srock, Palau International Coral Reef Center, Coral Reef Research Foundation, Palau Division of Marine Resources, Palau Ministry of Resources & Development. We also thank two reviewers for their constructive feedback and comments on the manuscript. HCW was a graduate student in the lab of AGG during the execution of this project. Major funding for this work was provided to AGG by the American Society for Mass Spectrometry, the Mellon Foundation, and the National Science Foundation (Chemical Oceanography, OCE#0426022 and 0610487).
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