Assessing the effects of carboxylated amino acids and polysaccharides on the fluid-calcite element partitioning

评估羧化氨基酸和多糖对流体-方解石元素分配的影响

• 批准号: 1536743
• 负责人: Joji Uchikawa
• 金额: $ 33.08万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-15 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1536743&HistoricalAwards=false
• 关键词: Assessing; effects; carboxylated; amino; acids

Many marine organisms build elaborate skeletons and shells made of carbonate minerals. Organic molecules such as amino acids and carbohydrates play important roles in regulating the structure and texture of these carbonates. Recent studies show that certain amino acids enhance magnesium uptake in carbonates and thereby influence the overall chemical composition. It is likely that these organic molecules influence the uptake of other elements as well, though this idea has not been tested. Using carefully controlled laboratory experiments, this study will investigate the effect of organic molecules on the abundance of several trace elements in carbonates. Trace element compositions of marine biogenic carbonates are widely used as tools ("proxies") to infer the temperature and the chemistry of ancient seawater, though it is known that biological processes also influence the shell chemistry. The outcome of this study will improve the reliability of trace element proxies by providing insights into biological controls on carbonate formation. This should advance our ability to reconstruct the dynamics, biology, and chemistry of the oceans in the past, which is a key to understanding the Earth's climate system. The research outcomes should be also relevant to other areas, such as removal of toxic heavy metals from the environment, engineering of new synthetic materials for industrial purposes, and geological CO2 sequestration. Based on inorganic calcite precipitation experiments using a pH-stat system, the research team will determine if and by how much element/Ca ratios in CaCO3 and precipitation rates depend on the types and concentrations of organic molecules at a constant saturation level. The research team will also address whether such effects are due to modulation of precipitation rates (kinetic effects) or due to direct molecular/ionic interactions by performing additional experiments using a known calcite precipitation inhibitor. This project provides support for an early-career investigator as well as research opportunities for undergraduate students at the University of Hawaii, where the student population has an exceptionally diverse ethnic background.

许多海洋生物会建造由碳酸盐矿物质制成的精美骨骼和贝壳。有机分子（例如氨基酸和碳水化合物）在调节这些碳酸盐的结构和质地方面起着重要作用。最近的研究表明，某些氨基酸可增强碳酸盐的镁摄取，从而影响整体化学成分。这些有机分子可能也会影响其他元素的吸收，尽管该想法尚未进行测试。使用精心控制的实验室实验，这项研究将研究有机分子对碳酸盐中几种痕量元素的丰度的影响。海洋生物碳酸盐的痕量元素组成被广泛用作推断古代海水的温度和化学的工具（“代理”），尽管众所周知，生物学过程也会影响壳化学。这项研究的结果将通过提供对碳酸盐形成的生物控制的见解来提高痕量元素代理的可靠性。这应该提高我们过去重建海洋动力学，生物学和化学的能力，这是理解地球气候系统的关键。研究结果也应与其他领域有关，例如从环境中去除有毒的重金属，用于工业目的的新合成材料以及地质二氧化碳隔离。基于使用pH-STAT系统的无机方解石沉淀实验，研究团队将确定CACO3中的元素/Ca比和降水速率的元素/CA比是否取决于恒定饱和水平下有机分子的类型和浓度。研究团队还将解决此类效果是否是由于对降水速率（动力学效应）的调节，还是由于使用已知的方解石沉淀抑制剂进行其他实验，是由于直接分子/离子相互作用引起的。该项目为夏威夷大学的本科生提供了早期职业研究员的支持，并为学生群​​体具有异常多样的种族背景提供了支持。