Effects of carbonate chemistry and calcium ions on the boron partitioning between aqueous solution and inorganic calcium carbonate

溶解的硼是天然海水的重要组成部分，它与钙的比例可以用来估计过去大气中二氧化碳的浓度——这是气候研究中非常需要的工具。然而，目前，硼与无机碳酸盐以及生物碳酸盐结合的机制在很大程度上仍然未知，这削弱了硼作为评估过去气候的工具的效用。夏威夷大学的研究人员将通过(1)进行受控的无机沉淀实验来分析碳酸钙样品中的B/Ca比率，(2)建立一个理论的热力学框架，将硼无机结合到碳酸盐中，作为溶液化学的功能，来阐明这些过程。(3)以现有的生物系统数据和无机骨架为基准，解释硼在生物成因碳酸盐中的掺入特征。这一研究结果将进一步加深对碳酸盐矿物中微量元素掺入过程的认识，对反应机制、代用物发育、气候学和全球生物地球化学循环等方面的研究具有重要意义。更广泛的影响：该项目将为夏威夷大学的研究生和本科生提供科学研究经验和教育，并通过夏威夷大学和檀香山的主教博物馆进行公众宣传。

Dissolved boron is an important constituent of natural seawater, and its ratio with calcium can be used to estimate concentrations of atmospheric carbon dioxide in the past - a highly desired tool in climate research. However, at present, the mechanism of boron incorporation into inorganic, as well as biogenic carbonates is still largely unknown, impairing the utility of boron as a tool to estimate past climate. Researchers from University of Hawaii will aim to shed light on these processes by (1) conducting controlled inorganic precipitation experiments to analyze B/Ca ratios in calcium carbonate samples, (2) developing a theoretical, thermodynamic framework for the inorganic incorporation of boron into carbonates as a function of the solution chemistry, and (3) using available data of biological systems and the inorganic framework as a baseline to explain features of boron incorporation into biogenic carbonates. Results from this study will advance fundamental understanding of trace element incorporation into carbonate minerals, which has important implications for research focusing on reaction mechanisms, proxy development, climatology, and global biogeochemical cycles.Broader Impacts: This project will provide scientific research experience and education to graduate and undergraduate students at the University of Hawaii, and conduct public outreach through the University of Hawaii and Bishop Museum in Honolulu.