This project will conduct deep-dwelling sclerosponges from a range of depths and sites in the western Pacific Ocean and examine the changes in skeletal chemistry over the last hundred years or more, with at least biannual resolution. Oxygen isotopes can serve as tracers for changes in ocean temperature and therefore help to determine the pattern of long-term variation (decadal to centennial). Thermistors will be deployed at each site, and monthly water samples will be collected to ground-truth analyses. Age control will be accomplished through U/Th dating and trends of anthropogenic carbon isotopes.
