Diffusion Coefficients of Dissolved Carbonate Species and CaCO 3 Dissolution in Deep-Sea Sediments

研究碳酸钙颗粒在海底的溶解正在进行中。实验室扩散池研究旨在确定溶解碳酸盐类沉积物的有效扩散系数。这项工作将有助于确定溶解速率是否受到海水和孔隙水之间扩散交换或反应动力学的限制。实地试验旨在确定赤道西大西洋方解石饱和层上下底栖有机碳和碳酸钙碳的再循环率。这项研究的一个主要目标是确定地表沉积物中有机物的氧化在多大程度上促进了溶解。将使用最新完善的微电极技术制作pH和pCO2的原位高分辨率孔隙水剖面。该野外工作计划与R. Jaknke的底栖腔通量测量以及Martin和Sayles的原位全岩心挤压法一起在Ceara Rise地区进行。初步测试和方法的相互比较正在美国东南部大陆边缘进行。

Research is underway to study the dissolution of calcium carbonate particles on the ocean floor. The laboratory diffusion-cell study is designed to determine the effective diffusion coefficients of the dissolved carbonate species sediments. This effort will help to determine whether the dissolution rates are limited by diffusive exchange between seawater and pore waters or by reaction kinetics. The field experiment is designed to determine rates of recycling of benthic organic carbon and calcium carbonate carbon above and below the calcite saturation horizon in the western equatorial Atlantic Ocean. A primary goal of the research is to determine to what extent the dissolution is enhanced by the oxidation of organic matter within surface sediments. In situ high resolution pore water profiles of pH and pCO2 will be made using newly perfected microelectrode techniques. The field work is planned for the Ceara Rise area in conjunction with benthic chamber flux measurements by R. Jaknke and with in situ whole core squeezer methods by Martin and Sayles. Preliminary testing and intercomparison of methods is being done in the southeastern U.S. continental margin.