This project will determine the concentration and carbon isotopic composition (d13C) of dissolved inorganic carbon (DIC) in deep-sea pore water, in order to provide a direct measure of the ratio of organic carbon oxidation to CaCO3 dissolution in the sediments. These data will be used to test the hypothesis that benthic organic matter oxidation drives CaCO3 dissolution in sediments overlain by bottom water which is supersaturated with respect to calcite. These study will be carried out in two separately-funded cruises which are focused on the benthic carbon cycle. This collaborative effort will enable limitations in the existing pore water d13C data to be overcome; at the same time, the d13C results will make a valuable contribution to these studies, by providing independent estimates of the rate and vertical distribution of benthic CaCO3 dissolution.
