Deep-Sea Corals: A New Ocean Archive

Deep-sea corals are an extraordinary new archive of deep ocean behavior. Through their relatively slow growth rates and intermediate to abyssal depth habitats, these species can record deep ocean changes in chemistry and circulation at sub-decadal timescales. The species Desmophyllum cristagalli is a solitary coral composed of uranium rich, density banded aragonite. Modern specimens from dredge collections can be used to calibrate paleoceanographic tracers and study this species ' growth rates and patterns. Using a newly developed ICP-MS age screening method, large numbers of samples can be processed relatively quickly and inexpensively to uncover interesting corals for further analysis. Fossil specimens can constrain two important problems in current paleoclimate research: the deep ocean's behavior during rapid climate changes in the past glacial cycle and the rate of deep ocean circulation in the past. Calibration of D. cristagalli using modern samples shows that the stable isotope tracers 8180 and 813C are severely affected by the coral's biologically mediated calcification. The magnitude of this "vital effect " is directly related to the banding pattern within a singl