HR: 11:05h
AN: PP42A-03    [Abstracts]
TI: High Resolution Coral Cd Measurements Using LA-ICP-MS and ID-ICP-MS: Calibration and Interpretation
AU: * Matthews, K A
EM: katiematthews@gmail.com
AF: Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, PA 19130, United States
AU: Grottoli, A G
EM: grottoli.1@osu.edu
AF: School of Earth Sciences, The Ohio State University, Columbus, OH 43210, United States
AU: McDonough, W F
EM: mcdonoug@geol.umd.edu
AF: Department of Geology, University of Maryland, College Park, MD 20742, United States
AU: Palardy, J E
EM: jpalardy@brown.edu
AF: Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, United States
AB: Cadmium in coral skeleton ([Cd]_coral) tracks oceanic upwelling. This study assessed the Cd signal in three species of coral ( Porites lobata, Pavona gigantea, Pavona clavus) from a seasonally upwelling region (Gulf of Panamá, Pacific Ocean) using high-resolution laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Single LA tracks in all species yielded variable results, however the average of multiple paths mirrored changes in in situ seawater Cd ([Cd]_sw). In addition, averaged P. clavus data from LA-ICP-MS was correlated to isotope dilution-ICP-MS data, albeit with lower concentrations using the latter method. Although the seawater and coral time series trends were similar, maximum [Cd]_coral preceded [Cd]_sw by approximately 1 month. When applying this 1-month offset, [Cd]_coral was well correlated to [Cd]_sw, providing the first direct calibration for this upwelling proxy (distribution coefficient = 1.3-1.7). A three year record of cyclic [Cd]_coral demonstrated the ability of LA-ICP-MS to rapidly generate long records for paleoupwelling reconstruction. Further improvements in measurement precision would make this technique comparable to existing ID-ICP-MS methods, but with higher sample throughput and temporal resolution.
DE: 0424 Biosignatures and proxies
DE: 0489 Trace element cycling (4875)
DE: 4220 Coral reef systems (4916)
DE: 4803 Analytical chemistry
DE: 4964 Upwelling (4279)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting