Benthic Mineralization of Organic Matter on the Continental Rise and the Dissolution of CaCO 3 at the Deep Sea Floor

该项目是对海底有机物循环和成岩作用研究的继续。要评估海洋过程对全球气候的影响并正确解释沉积记录，就需要了解沉积物中生物元素的沉积通量、循环速率和埋藏速率。该项目的最新结果提出了关于海底沉积物中CaCO 3溶解的问题，这是由于CO2在孔隙水中代谢释放的结果。底栖通量室的碱度变化模型预测了沉积物的碱度通量，但该室的数据显示，在海底部署过程中几乎没有碱度通量。本研究的目的是1.确定深海沉积物中代谢释放的CO2对CaCO 3溶解的影响; 2.确定能准确反映CaCO 3在土壤中溶解的动力学表达式。该项目的第一部分包括到北卡罗来纳州外的大陆坡进行一次短途航行，以测试一种新的高压沉积物采样器，并对P.I.该项目正在与Sayles和Martin（使用钢丝绳原位整个岩心挤压器）和Reimers（使用PCO 2微电极）在同一主题上的工作进行协调。短期测试航行提供了一个测试所有设备的机会，此外，还可以提供预测有机碳流入海底的通量很高但底层沃茨中CaCO 3饱和的区域的碳酸盐溶解数据。工作的主要部分将集中在塞阿拉海隆-圭亚那盆地区域，在该区域，CaCO 3不饱和的南极底层水的存在将导致显著的可测量溶解。将把海底通量室（本项目）测量的碳酸盐系统参数的海底通量与其他技术的结果进行比较。

This project is a continuation of a study of the cycling and diagenesis of organic matter at the sea floor. Knowledge of the deposition flux, cycling rate and burial rate of biogenic elements in sediments is required to assess the influence of ocean processes on global climate and to properly interpret the sedimentary record. Recent results from this project have raised questions about the dissolution of CaCO3 from sea floor sediments as a result of CO2 metabolically released in the pore water. Models of the alkalinity change in benthic flux chambers predict an alkalinity flux from the sediments, but the chamber data show little if any alkalinity flux during sea floor deployments. The goals of the present research are 1. To determine the influence of metabolically released CO2 on the dissolution of CaCO3 in deep sea sediments; 2. To determine the kinetic expression that accurately represents CaCO3 dissolution on the dea floor. The first part of the project consists of a short cruise to the continental slope off North Carolina to test a new High Pressure Sediment Sampler and some alterations to the benthic chambers by the P.I. The project is being coordinated with work on the same topic by Sayles and Martin (using a wire-line in situ whole core squeezer) and by Reimers (using PCO2 microelectrodes. The short test cruise provides an opportunity to test all the equipment and in addition may provide date on carbonate dissolution in an area where flux of organic carbon to the sea floor is predicted to be high, but bottom waters are saturated with CaCO3. The major portion of the work will be focussed on the Ceara Rise- guiana Basin region where the presence of Antarctic Bottom Water undersaturated with CaCO3 should cause significant measurable dissolution. The sea floor fluxes of carbonate system parameters measured by the in situ benthic flux chambers (this project) will be compared to the results from the other techniques.