The Solubility of Biogenic Calcite

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A primary focus of research in marine chemistry involves defining the role of the oceans in the earth's carbon cycle, including the role of oceanic uptake of anthropogenic CO2. Research has shown that calcium carbonate, or calcite (CaCO3), dissolution in the ocean is a significant mechanism for CO2 neutralization. However, recent data has implied that differences in the solubility of biogenic calcite and inorganically precipitated calcite may exist. Given the important role played by the value of calcite solubility in assessing the proposed mechanisms of dissolution (bottom water undersaturation vs. metabolic acid addition) and in developing kinetic models of dissolution, a scientist from Woods Hole Oceanographic Institution plans to re-evaluate calcite solubility with new experiments. Specifically, the following experiments would be carried out: (1) measure the solubility of inorganically precipitated calcite, (2) measure both bulk foraminiferal calcite and individual species of planktonic foraminifera covering a range of dissolution susceptibility, (3) measure the physical and chemical properties of calcite; and (4) determine the effect of organic coatings on the equilibration of calcite with seawater in a new study of the solubility of biogenic calcite. Results from this study would be used to redefine parameters for inclusion into long term models of carbon uptake in the oceansAs regards broader impacts, results from the research would be incorporated into lectures for undergraduate and graduate courses. It is anticipated that summer student fellows would participate in the calcite solubility studies during the first two years of the project. In addition, high school students would be included in the study to get experience with sample preparation and foraminifera picking procedures.