A new high pressure liquid chromatography system for in situ measurements in marine pore waters

PIs申请资金用于开发一种基于高压液相色谱和伏安技术的新型水下仪器，以测量任何水深海洋沉积物中孔隙水阴离子、阳离子和氧化还原物质的浓度。本项目开发的仪器将是第一个将高效液相色谱方法应用于海洋沉积物孔隙水的原位地球化学分析，并将该高效液相色谱系统与现有的原位电化学分析仪相结合的仪器。该仪器将受益于微孔技术的最新发展，以限制废水的消耗，使其能够长期部署。这一仪器将补充已有的用于海洋沉积物现场测量的若干商业仪器。更重要的是，该仪器将首次提供一种方法来确定参与早期成岩过程的阴离子、阳离子和氧化还原物质的垂直分布。氯化物是一种化学示踪剂，用于追踪河口沉积物的混合过程和热液系统的相分离。氮种可以提供沉积物中反硝化、异化还原成铵（DNRA）和硝化过程的信息。硫酸盐还原是沿海沉积物和近冷渗漏中一个重要的终端电子接受过程，它可以耗尽孔隙水中的硫酸盐。最后，钙和镁是天然有机物再矿化过程、碳酸盐溶解和沉淀过程以及淡水与海水混合的示踪剂。更广泛的影响：正如他在过去的研究中所做的那样，PI将积极地让本科生和研究生参与他在这里的工作。他还将像过去一样，将他在研究中使用的技术纳入本科实地研究课程。这对学生的教育和海洋科学界都有好处。两位PI都参与了K12的推广工作。

The PIs request funding to develop a new underwater instrument based on high pressure liquid chromatographic and voltammetric techniques to measure the concentrations of pore wateranions, cations, and redox species in situ in marine sediments at any water depth.The instrument developed during this project will be the first to adapt HPLC methods for the in situ geochemical analysis of pore waters in marine sediments and couple this HPLC system to existing in situ electrochemical analyzers. This instrument will benefit from the recent developments in microbore technology to limit consumption of effluents such that it will be deployable for long periods of time. This instrument will complement a number of commercial instruments already available for in situ measurements in marine sediments. More importantly, this instrument will for the first time provide a mean to determine the vertical distribution of anions, cations, and redox species involved in early diagenetic processes. Chloride is a chemical tracer that has been used to trace mixing processes in estuarine sediments and phase separation in hydrothermal systems. Nitrogen species can provide information on denitrification, dissimilatory reduction to ammonium (DNRA), and nitrification processes in sediments. Sulfate reduction is a significant terminal electron accepting process in coastal sediments and near cold seeps that can deplete sulfate from pore waters. Finally, calcium and magnesium are tracers of natural organic matter remineralization processes, carbonate dissolution and precipitation processes, and mixing of freshwater with marine waters. Broader Impacts: The PI will actively involve both undergraduate and graduate students in his work here, as he has done in past studies. He will also incorporate the technology he uses in his research into an undergraduate field studies class as he has done in the past. This is good for the education of the students and good for the marine science community. Both PI's are involved in K12 outreach efforts.