Collaborative Research: CaCO3 Dissolution in the North Pacific Ocean: Comparison of Lab and Field Rates with Biogenic and Abiogenic Carbonates

海洋酸化是由于海洋从大气中吸收更多的人为二氧化碳(CO2)而导致的海水pH值的下降。这种吸收在海洋环境中的影响因碳酸钙(CaCO3)溶解成钙离子和碳酸盐离子而减弱，允许碳酸盐离子结合导致pH下降的自由氢离子。南加州大学和加州理工学院的研究人员已经开发出一种新的方法来确定碳酸盐的溶解速度，这种方法在实验室和现场都有效。使用这项技术的初步数据显示，在实验室和现场测得的速率有明显的差异。实验室和现场测量标准化是至关重要的，以便能够准确地研究和比较溶出度研究。因此，研究人员将进行广泛的野外工作和实验室，以弥合这些溶出率测量之间的差距。这些结果将对海洋化学界，特别是希望研究海洋碳酸盐化学的任何方面的模型师，以及使用碳酸盐材料研究过去海洋状况的古海洋学家都有广泛的帮助。研究生将由研究人员共同指导，南加州大学S(南加州大学)青年研究员项目将允许研究人员吸收当地高中生参与。南加州大学国际关系系的学生将参与该项目，不仅获得科学经验，还将学习科学政策方面的知识。碳酸钙(CaCO_3)的溶解有助于缓解海洋酸化(OA)的影响，是海洋-S碱度平衡的关键因素。研究人员最近开发了一种新的示踪方法，可以在实验室和现场监测碳酸盐的溶解速度。该方法跟踪13C从标记固体到海水的转移。使用这种方法在理解碳酸钙溶解动力学控制方面取得了突破，但它也揭示了实验室和现场的测量结果并不完全一致。能够将这两个测量结果关联起来，以便能够充分研究和了解CaCO3的溶解动力学是至关重要的。因此，研究人员将扩展他们之前的工作，使实验室中的测量结果与海洋中的测量结果标准化。这项实地研究将使用具有碳酸盐饱和状态梯度的北太平洋，基于实验室的实验将允许研究人员限制变量，如压力、溶解的无机碳/碱度比和磷酸盐浓度。这项研究将进一步了解海洋酸化、控制碳酸盐溶解的机制以及海洋如何调节其碱度收支。

Ocean acidification (OA) is the decrease in seawater pH due to increased oceanic uptake of anthropogenic carbon dioxide (CO2) from the atmosphere. The impact of this uptake in the marine environment is lessened by the dissolution of calcium carbonate (CaCO3) to calcium and carbonate ions, allowing carbonate ions to bind free hydrogen ions that cause the decrease in pH. Researchers from the University of Southern California and California Institute of Technology have developed a new method for determining carbonate dissolution rates that work in both laboratory and field settings. Preliminary data using this technique has revealed a distinct difference in measured rates between those obtained in the laboratory and those in the field. It is crucial that laboratory and field measurements be standardized to be able to accurately study and compare dissolution rate studies. As such, the researchers will perform extensive fieldwork and laboratory to bridge the gap between these dissolution rate measurements. Results will be widely useful to the ocean chemistry community, especially modelers, wishing to study any aspect of ocean carbonate chemistry, as well as paleoceanographers using carbonate material to study past ocean conditions. Graduate students will be co-mentored by the researchers, and the University of Southern California?s (USC) Young Researcher Program will allow the researchers to involve local high school students. USC International Relations students will be involved in the project, not only gaining scientific experience, but also will learn the policy aspect of the science.Calcium carbonate (CaCO3) dissolution helps to mitigate the effects of ocean acidification (OA) and is a key factor in the ocean?s alkalinity balance. The researchers have recently developed a novel tracer methodology which can monitor carbonate dissolution rates in both the lab and field. This method traces the transfer of 13C from labeled solids to seawater. Using this method has led to breakthroughs in understanding the controls of CaCO3 dissolution kinetics, but it has also revealed that the measurements made in a lab and in the field are not entirely in line. It is crucial to be able to correlate these two measurements to be able to fully study and understand the dynamics of CaCO3 dissolution. Therefore, the researchers will extend their previous work to standardize the results of measurements in the lab with those in the ocean. The North Pacific Ocean with a gradient in carbonate saturation states will be used for the field study, and lab-based experiments will allow the researchers to constrain variables such as pressure, the dissolved inorganic carbon/alkalinity ratio, and concentrations of phosphate. This research will further understanding of OA, the mechanisms controlling carbonate dissolution, and how the ocean modulates its alkalinity budget.