High rates of organic matter degradation near the sediment- water interface together with slow CaCO3 dissolution are expected to result in pore waters that are undersaturated with respect to calcium carbonate to depths exceeding 57cm in heimpelagic sediments. This hypothesis will be tested by determining the effective in situ CaCO3 dissolution rate constant and estimating integrated rates of organic carbon and CaCO3 regeneration at three stations that underlie the California Current westward of Point Conception, California. In the first year, the thrust will be to further develop, calibrate and test PCO2 and pH micro- electrodes. Field work will be conducted both at the end of the first and the second year.
