Fundamental Investigation of Glacial/interglacial Deep-sea pH and Carbonate Saturation Effects on Paired Benthic Foraminiferal Trace Element and Stable Isotope Signatures

冰期/间冰期深海 pH 值和碳酸盐饱和度对底栖有孔虫微量元素和稳定同位素特征影响的基础研究

• 批准号: 0647891
• 负责人: Timothy Shaw
• 金额: $ 25.15万
• 依托单位: University South Carolina Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0647891&HistoricalAwards=false
• 关键词: Fundamental; Investigation; Glacial; interglacial; Deep

Trace elements and stable isotopes incorporated into the shells of deep-sea foraminifera record information on the ocean environment during their calcification. Paleoceanographers depend on these foraminiferal proxies to characterize past environmental conditions (i.e., temperature, salinity, glacial ice volumes). We hypothesize that pH excursions, manifested by changing CO2 concentrations in the deep sea, induce significant changes in the benthic foraminiferal biomineralization process, which in turn can lead to systematic offsets of trace element and isotope paleoproxy calibrations. We propose to measure the effect that pH has on metal incorporation into biogenic calcite grown under stringently-controlled environmental conditions in the laboratory. The University of South Carolina maintains the only long-term deep-sea benthic foraminiferal culturing system in the world specifically designed to experimentally-vary deep-sea trace element and pH conditions. The experimental pH range is chosen to represent chemistries in the deep-ocean without reproducing in situ pressures. This project will broaden our understanding of proxy response to varying environmental conditions relevant to past and present deep-ocean chemistries and improve our knowledge of the dynamic ocean-atmosphere system. It will directly support at least two graduate student theses and two undergraduate science majors and will involve traditionally under-represented groups in science at the undergraduate and graduate levels.

深海有孔虫壳层中含有的微量元素和稳定同位素记录了其钙化过程中海洋环境的信息。古海洋学家依靠这些有孔虫替代物来描述过去的环境条件(即温度、盐度、冰川冰量)。我们假设，深海中CO2浓度的变化所表现出的pH漂移，会导致海底有孔虫生物矿化过程的显著变化，这反过来又会导致微量元素和同位素古代用定标的系统偏差。我们建议在实验室中测量pH对在严格控制的环境条件下生长的生物方解石中金属掺入的影响。南卡罗来纳大学维护着世界上唯一一个长期的深海底栖有孔虫养殖系统，该系统专门为实验性地改变深海微量元素和pH条件而设计。实验的pH范围被选择来表示深海中的化学成分，而不会再现原地压力。这个项目将扩大我们对与过去和现在的深海化学有关的不同环境条件的替代反应的理解，并增进我们对动态海洋-大气系统的了解。它将直接支持至少两个研究生论文和两个本科理科专业，并将涉及在本科和研究生层面上传统上代表不足的理科群体。