NSFOCE-BSF: Foraminiferal Na/Ca: a new proxy for reconstructing Cenozoic seawater composition

NSFOCE-BSF：有孔虫Na/Ca：重建新生代海水成分的新代理

基本信息

批准号：
1634573
负责人：
Yair Rosenthal
金额：
$ 38.75万
依托单位：
Rutgers University New Brunswick
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2016
资助国家：
美国
起止时间：
2016-09-15 至 2019-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1634573&HistoricalAwards=false
关键词：
NSFOCE BSF Foraminiferal Na Ca

项目摘要

Variations in the composition of seawater have important implications for Earth climate and biological processes in the ocean because of their relation to the carbon cycle. Specifically, the history of calcium concentration in the ocean over the Cenozoic (past ~65 million years) is tightly linked to chemical weathering of silicate and carbonate rocks on land and the precipitation and dissolution of carbonate minerals in the ocean, processes that control long-term changes in atmospheric carbon dioxide concentration and thus strongly influence global climate. Given the current acceleration of biogeochemical cycling due to the increase in greenhouse gases, these past processes may provide insights to future conditions that have no modern analogs. This research seeks to develop a new method of reconstructing variability in calcium in the oceans using comparison to seawater sodium concentrations, which are thought to be constant on timescales of many tens of millions of years. The project is funded through a special opportunity for U.S.-Israeli collaboration in ocean sciences. The project will train a U.S. post-doc and two Israeli graduate students who will spend time at both labs and will interact with the two principal investigators. The project also involves several undergraduate students who will be trained in various laboratory activities. Specifically, this research will provide a new method to reconstruct Cenozoic seawater calcium concentrations ([Ca]) using foraminiferal Na/Ca. Culture experiments (led by the Israeli team) and core top calibrations (led by the U.S. team) will be undertaken to further validate preliminary observations and generate records of Na/Ca and other elemental ratios in benthic foraminifera as means for reconstructing Cenozoic seawater chemistry. Culture experiments of benthic (Operculina ammonoides, Ammonia tepida and Amphistegina lobifera) and planktonic (G. ruber and G. siphnifera) foraminifera will be used to determine the distribution coefficients of Na/Ca and the other elements discussed above at different seawater [Ca] and under variable and constant calcite saturation conditions. The results from these experiments and core top calibrations will be used to generate a complete Na/Ca record for the last 55 Myr.

海水组成的变化对地球气候和海洋中的生物过程具有重要意义，因为它们与碳循环有关系。具体而言，在新生代（过去约6500万年）上，海洋中钙浓度的历史与陆地上的硅酸盐和碳酸盐岩的化学风化紧密相关，以及在海洋中碳酸盐矿物质的沉淀和溶解，这些过程控制长期的过程大气二氧化碳浓度的项变化，从而强烈影响全球气候。鉴于由于温室气体增加而导致的生物地球化学循环加速，这些过去的过程可能会为没有现代类似物的未来条件提供见解。这项研究旨在使用与海水钠浓度进行比较，以开发一种新的方法来重建海洋钙的变异性，这被认为在数千万年内的时间尺度上是恒定的。该项目是通过在海洋科学合作的美国 - 以色列合作的特殊机会来资助的。该项目将培训一名美国大会后和两名以色列研究生，他们将在两个实验室度过时光，并将与两位主要调查员进行互动。该项目还涉及几位将在各种实验室活动中接受培训的本科生。具体而言，这项研究将提供一种新方法，使用有孔虫Na/Ca重建新生代的海水钙浓度（[CA]）。将进行文化实验（由以色列团队领导）和核心顶级校准（由美国团队领导），以进一步验证初步观察结果，并在底栖有孔虫中产生NA/CA和其他元素比率的记录，以作为重建碳氧化海水化学的手段。底栖（Operculina ammonoides，氨基氨基氨基和二甲苯二甲体）和浮游生物（G. Ruber和G. siphnifera）的培养实验将用于确定Na/ca的分布系数以及上面在不同的海水[CA]上讨论的其他元素[]并在可变且恒定的方解石饱和条件下。这些实验和核心顶部校准的结果将用于为最后55 MYR生成完整的NA/CA记录。