Mineralization of Organic Matter and Dissolution of CaCO3 atthe Deep Sea Floor

9617297 Jahnke控制溶解的CaCO 3的因素的知识，因此，保存，是至关重要的CaCO 3沉积记录的解释和预测之间的联系沉积CaCO 3，海洋化学和过程，和未来的气候。最近的研究结果表明，几个方面的碳酸钙溶解，特别是溶解驱动的代谢产物的二氧化碳在沉积物孔隙沃茨，约束不足。这一点已被证明：1。在原位底栖通量室孵育中观察到的代谢溶解程度的区域变化，2.从现场孔隙水研究中计算的溶解速率在饱和层中缺乏显著变化，以及3.表层沉积物中的文石存在于不饱和的底层沃茨之上。之前已经研究过的三个地区中的两个地区，即佛得角高原、翁通爪哇高原和哈特拉斯角大陆隆起，将被重新审视，以进一步限制CaCO 3的溶解机制。具体而言，将在原位温度和压力下分析细尺度孔隙水样品中的Ca 2+和痕量金属。这些结果将扩大以前已经获得的这些地区的数据集。此外，还将进行原位底栖通量箱培养，以：1.检查腔室伪影是否影响了先前的结果，2.确定细尺度孔隙水Ca2+梯度是否支持目前的溶解模型，并与室测量一致，3.检查其他酸碱反应是否影响预测的代谢溶解速率，4.评估研究地点之间碳酸盐相的矿物学和反应性的变化，以及5.确定碳酸盐矿物表面的交换反应是否可以解释观察到的代谢溶解的变化。***

9617297 Jahnke Knowledge of the factors that control dissolution of CaCO3 and hence, preservation, is critical to the interpretation of the CaCO3 sedimentary record and to the prediction of the linkages between sedimentary CaCO3 , ocean chemistry and processes, and future climates. Recent results indicate that several aspects of CaCO3 dissolution, especially dissolution driven by the metabolic production of CO2 in sediment pore waters, are poorly constrained. This has been demonstrated by: 1. regional variations in the extent of metabolic dissolution observed in in situ benthic flux chamber incubations, 2. the lack of significant change in the rate of dissolution calculated from in situ pore water studies across the saturation horizon, and 3. the presence of aragonite in surface sediments that are overlain by undersaturated bottom waters. Two of the three regions, the Cape Verde Plateau, Ontong Java Plateau and Cape Hatteras continental rise, that have been studied previously will be revisited to further constrain CaCO3 dissolution mechanisms. Specifically, fine- scale pore water samples at in situ temperature and pressure will be analyzed for Ca2+ and trace metals. These results will augment the data sets already obtained for these regions previously. In addition, in situ benthic flux chamber incubations will be conducted to: 1. examine whether chamber artifacts have influenced previous results, 2. determine if fine-scale pore water Ca2+ gradients support present dissolution models and agree with chamber measurements, 3. examine whether other acid base reactions are influencing predicted metabolic dissolution rates, 4. assess variations in the mineralogy and reactivity of the carbonate phases between the study sites, and 5. determine whether exchange reactions at the carbonate mineral surface can account for the variations in metabolic dissolution observed. ***