In Situ Measurements of Calcium Carbonate Dissolution Rates

CaCO 3溶解是全球 CO2的循环。 各种方法被用来研究 碳酸盐溶解速率.实验室原位试验 在水柱中的溶解实验和建模， 与沉积物中观察到的%CaC03的分布进行比较。 这项工作提供了原位溶解速率的测量 使用海底通量室。 将进行直接测量 通过测量进入腔室的钙流量;间接 将通过建立预算来进行测量， 基于碱度的测量， 二氧化碳，氧气和硝酸盐通量. 一个数值模型来模拟 孔隙水碳酸盐离子浓度和溶解通量 将与观察到的数据进行比较，并用于估计体积 碳酸盐溶解速率常数 的准确性 模型和预测的速率常数将通过 将酸注入腔室水中并监测 碱度、CO2和钙的响应。 测量 营养盐、氡和氧通量，由孔隙水增加 剖面，将用于约束成岩反应 发生在研究的地点。 执行本研究 这两个地区包括一系列沉积物类型，盆地 加州边境和东部的一个样带 赤道太平洋

CaCO3 dissolution is an important component in the global cycling of C02. Various approaches have been used to study carbonate dissolution rates; laboratory experiments, in situ dissolution experiments in the water column and modeling to compare with observed distributions of %CaC03 in sediments. This work provides measurements of in situ dissolution rates using benthic flux chambers. Direct measurements will be made by measuring the flux of calcium into a chamber; indirect measurements will be made by establishing a budget for alkalinity in the chamber, based on measurements of alkalinity, C02, oxygen and nitrate fluxes. A numerical model to simulate pore water carbonate ion concentration and dissolution fluxes will be compared to observed data and used to estimate the bulk carbonate dissolution rate constant. The accuracy of the model and the predicted rate constants will be tested by injecting acid into the chamber water and monitoring the response of alkalinity, C02 and calcium. Measurements of nutrient, radon and oxygen fluxes, augmented by pore water profiles, will be used to constrain the diagenetic reactions occuring at the sites studied. This study will be conducted in two regions that include a range of sediment types, the basins of the California borderland and a transect in the Eastern equatorial Pacific.