Collaborative Research: Calibration of Raman Spectroscopy for calcite saturation state in marine biogenic calcification

合作研究：海洋生物钙化中方解石饱和状态的拉曼光谱校准

• 批准号: 2323222
• 负责人: Thomas DeCarlo
• 金额: $ 15.23万
• 依托单位: Hawaii Pacific University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2323222&HistoricalAwards=false
• 关键词: Collaborative; Research; Calibration; Raman; Spectroscopy

Much of the anthropogenic CO2 released into the atmosphere has been absorbed by the ocean, which acts as a buffer against global warming and rapid climate change. But this makes seawater more acidic and corrosive to CaCO3 minerals (known as ocean acidification: OA), which is expected to harm marine organisms that build skeletons or shells from CaCO3 (marine calcifiers). Marine calcifiers typically grow their CaCO3 hard parts in a micro-scale “calcifying fluid (CF)” by modifying its chemistry from seawater to elevate the degrees of CaCO3 saturation (Ω). This process potentially enables calcifiers to cope with OA, at least to some extent. This research aims to establish the use of Raman Spectroscopy (RS) to constrain Ω of CF. Compared to other methods, this approach will be simple, rapid, and non-destructive to organisms and CaCO3 samples. This work will be a cornerstone for an important methodology that can advance knowledge on calcification mechanisms and resilience of marine calcifiers against OA. Rapid precipitation of CaCO3 at higher Ω levels leads to greater structural disorder in the mineral lattice due to increased defects and kinetically-driven uptake of minor/trace elements (e.g., Mg). Thus, the degree of lattice disorder determined from the positional shift in and width of Raman peaks should be a function of Ω. This concept has been validated for aragonites and RS has been extensively used to constrain Ω of CF in aragonitic calcifiers. But in calcites, Mg inclusion by substitution of Ca also contributes to structural disorder significantly. This necessitates a correction for Mg-driven lattice disorder for effective use of RS on calcitic organisms, which is currently lacking. This research will produce an extensive set of abiogenic calcite samples that vary significantly in Mg contents and solution Ω for precipitation based on laboratory experiments using artificial seawater. These samples will disentangle the overlapping effect of Mg inclusion and Ω on calcite structural disorder. This investigation will for the first time generate Raman calibrations for Mg contents and Ω that are applicable to marine biogenic calcites. This project is jointly funded by the Geobiology and Low-Temperature Geochemistry Program (GG), the Established Program to Stimulate Competitive Research (EPSCoR), and the Marine Geology and Geochemistry Program (MGG).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

释放到大气中的大部分人为二氧化碳都被海洋吸收，这是防止全球变暖和快速气候变化的缓冲。但这使海水对CACO3矿物质（称为海洋酸化：OA）更具酸性和腐蚀性，这有望损害从Caco3（海洋钙化器）中建立骨骼或壳的海洋生物。海洋钙化物通常通过微尺度“钙化流体（CF）”来生长其CACO3硬零件，从而修改其化学因素从海水提高CACO3饱和度（ω）的程度。这个过程可能至少在某种程度上使钙化器能够应对OA。这项研究旨在建立拉曼光谱法（RS）来限制CF的ω。与其他方法相比，这种方法对生物和CACO3样品将是简单，快速且无损的。这项工作将是一种重要方法论的基石，可以提高有关计算机制和海洋钙化器对OA的弹性的知识。 CACO3在较高ω的水平上的快速沉淀导致矿物晶格的结构障碍更大，因为缺陷增加和动力学驱动的次要/微量元素的摄取（例如mg）。这是由拉曼峰的位置移动和宽度确定的晶格障碍程度应是ω的函数。该概念已被验证为Aragonites，RS已被广泛用于约束在军方钙化中CF的ω。但是在方解石中，通过替换CA的含量也会导致结构障碍。这是对MG驱动的晶格障碍的校正，以有效地使用RS在目前缺乏的钙化生物上。这项研究将产生一系列广泛的亚物质方解石样品，这些样品将首次改变这项投资，以基于实验室实验，使用人工海水生成了MG含量的拉曼校准和溶液ω。这些样品将消除MG纳入和ω对方解石结构障碍的重叠效果。该投资将首次生成适用于海洋生物刻度的MG含量和ω的拉曼校准。该项目由地质学和低温地球化学计划（GG）共同资助，刺激竞争研究的既定计划（EPSCOR）以及海洋地质学与地球化学计划（MGG）。这奖反映了NSF的立法使命，并通过评估通过基金会的知识优点和广泛的评论来获得评估，并被视为珍贵的支持。