Development and Evaluation of pH and CO2 Microelectrodes for In Situ Determination of Deep Sea Pore Water Carbonate Chemistry and Carbon Recycling Rate

本项目旨在开发一种基于平头irooxide pH微电极的快速稳定的pCO2微电极，并评估pH和pCO2传感器用于测量底栖碳循环速率和孔隙水CO2化学的准确性和适用性。pCO2微电极将是早期pCO2传感器的显著改进。计划提高和优化pCO2电极的响应速率、稳定性和精度。pH和pCO2微电极测量的准确性将通过分析各种实验室培养的沉积物并将结果与整个岩心挤压样品的TCO2浓度进行比较来评估。还将在两个沿海环境中进行实地测量和评价。未来的目标不仅是用微电极收集高分辨率和无伪影的原位剖面，而且还可以通过将原位微电极测量（O2，pH和pCO2）和原位采样技术（TA， TCO2和营养物质）结合在一个设备中来过度确定孔隙水碳酸盐岩系统。这些测量将确定有机碳早期成岩过程中的O2/C/N比值。该策略还将提供三种最先进的方法，微电极，整个核心挤压和底栖腔孵育，可靠性和内部一致性检查。这种综合方法对于确定底栖生物对碳输入季节变化的响应以及描述孔隙水碳酸盐岩系统和CaCO3保存和溶解的控制至关重要。

9401908 CAI This project is aimed at developing a fast and stable pCO2 microelectrode based on a flat tip Iroxide pH microelectrode and evaluating the accuracy and applicability of pH and pCO2 sensors for measuring benthic carbon recycling rates and pore water CO2 chemistry. The pCO2 microelectrode will be a marked improvement of an earlier pCO2 sensor. It is planned to enhance and optimize the response rate, stability, and precision of the pCO2 electrode. The accuracy of the pH and pCO2 microelectrode measurements will be evaluated by profiling various laboratory incubated sediments and comparing the results with TCO2 concentrations from whole core squeezing samples. In situ measurements and evaluation also will be conducted in two coastal environments. A goal in the future is not only to collect high resolution and artifact-free in situ profiles with microelectrodes, but also to over-determine the pore water carbonate system by combining the in situ microelectrode measurements (O2,pH, and pCO2) and the in situ sampling techniques (TA, TCO2, and nutrients) in a single device. The measurements will define the O2/C/N ratios during organic carbon early digenesis. This strategy will also give the three state-of-the-art approaches, microelectrode, whole core squeezing, and benthic chamber incubation, a reliability and internal consistency check. This combined approach is essential for determining benthic response to the seasonal changes of C input and in delineating controls over the pore water carbonate system and CaCO3 preser- vation and dissolution.