Diagenesis and CaCO3 Dissolution on the Ceara Rise, Equatorial Atlantic

点击翻译按钮获取中文摘要

This research project is a study of the dissolution of CaCO3 that results from the oxic degradation of organic matter in sediments overlain by supersaturated bottom waters. The work centers on determining the amounts of dissolution occurring over a range of depths and saturation states. The sampling and analysis scheme is designed to permit study of the stoichiometry of oxic organic matter degradation/CaCO3 dissolution, to constrain the rate constant of dissolution through analysis and modelling, and to evaluate the equilibrium constant for dissolution of sedimentary CaCO3. The field site is the Ceara Rise, and a transect from the crest of the Rise to the adjacent floor will be the source of pore water profiles of chemical species produced or consumed during organic carbon oxidation and CaCO3 dissolution. The samples will be taken by means of an in situ Whole Core Squeezer. This work is being coordinated with a separate project by Reimers to study pore water chemistry at the site with a microelectrode profiler technique, and another by Jahnke to measure benthic fluxes of the same parameters with a benthic flux chamber.