Place：SOO Meeting Room, Xuhui Campus
Deep-sea corals are one of the best archives of intermediate and deep waters in the ocean that capture rapid climate shifts over the last glacial cycle. Multiple paleoceanographic tracers (including radiocarbon, boron isotopes, B/Ca, nitrogen isotopes, clumped isotopes) have been developed in deep-sea corals (especially the species Desmophyllum dianthus) in the past decades to reveal the coupling between ocean dynamics, biogeochemistry and carbon cycle over the timescale of rapid climate change. Despite these advances, applications of traditional oceanographic tracers such as carbon and oxygen isotopes and Sr/Ca thermometer to deep-sea corals remain a challenge due to our insufficient understanding of the “vital effects”.
Deep-sea corals are ideal test organisms to study the mechanism underlying the vital effects, due to the large tracer gradients in individual corals living under relatively constant environmental conditions. Here we present stable isotope and trace metal (Me/Ca ratios) data in a suite of modern D.dianthus that span a wide range of environmental conditions. The data were collected over four different spatial scales in individual corals (bulk, micromill, SIMS, nanoSIMS), to build both empirical tracer calibrations and a mechanistic model of coral calcification.
On the bulk sample.
About the speaker:
Sang Chen is a paleoceanographer and geochemist by training. A geochemistry PhD from Caltech, Sang’s research is focused on the mechanisms of tracer incorporation into natural carbonate archives and their climate implications. Sang’s work spans a range of carbonate archives including speleothems, corals and authigenic aragonites, and involves multiple proxies of stable isotopes as well as minor and trace elements. Some particular research interests include long-term tropical hydroclimate variability, biomineralization in deep-sea corals and atomistic mechanisms of stable isotope/clumped isotope incorporation into calcium carbonates.