Project: Stable Isotopes and Strontium in Western Pacific Sclerosponges: Calibration and Applications to Paleoceanography

NSF Award Abstract:
Proxy records are extremely useful for reconstructing paleoceanographic/ paleoclimate conditions and hence understanding oceanographic and climate change, although these data must be well-calibrated. However, proxy tools to evaluate annual-to-centennial timescale variability of the stable isotopic composition of dissolved inorganic carbon and oxygen in seawater over the past several centuries in the Pacific or to evaluate these variables and seawater temperature across depth have not been fully developed. The western Pacific plays a large role in tropical and global climate and is therefore an ideal location to pursue this research.

A scientist at the University of Pennsylvania will quantitatively calibrate the sclerosponge, Acanthocheatetes wellsi, skeletal d13C, d18O, and strontium/calcium (Sr/Ca) to evaluate calibrated proxy records on annual-to-interdecadal timescales. The calibrations will then be applied to two high-resolution 50-year stable isotope and Sr/Ca records and the interannual-to-interdecadal timescale variability in the longer records will be evaluated by comparing them to available instrumental, satellite, and model output data.

The results will be a valuable tool for constraining existing carbon uptake models, initializing and testing ENSO models, and generally increasing our knowledge of the natural spatial and temporal variability in d13CDIC, d18Osw, and seawater temperature at the surface and across depth in the tropics.