Gulf of Alaska and California Bamboo Corals: A New Archive of Climate Change

Wilson Sauthoff

Abstract

Deep sea bamboo coral communities form along seamounts and continental margins with near global distribution. Deep ocean trawling, coral trading, and ocean acidification threaten these corals and associated species. Much like tropical corals, bamboo corals record surrounding ocean geochemistry as the coral skeleton is precipitated outwards from an internal core, sometimes displaying growth banding similar to tree rings. Records of ocean chemistry present reliable proxy records of changes in seawater conditions, such as productivity and nutrient content. Analysis of ocean variability may provide important indications of past frequency of climate oscillations, such as El Niño or Pacific Decadal Oscillation. Bamboo coral specimens from the California margin and Gulf of Alaska provide insight into latitudinal and temporal differences in sea surface productivity and nutrient availability. Past oceanic conditions are reconstructed using trace element profiles (Ba/Ca, Sr/Ca) to interpret past ocean nutrient levels and productivity. This research adds to the scientific understanding of natural, short-term climatic variability in the Pacific Ocean, and tests for evidence of anthropogenic changes in the deep ocean environment.   

Download the complete paper (PDF)