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Evolution of South Pacific Oxygen and Preformed Nutrient Changes over the Deglaciation

冰消期南太平洋氧气的演变和营养盐的变化

基本信息

批准号：
1851900
负责人：
Jean Lynch-Stieglitz
金额：
$ 38.47万
依托单位：
Georgia Tech Research Corporation
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-04-01 至 2024-03-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1851900&HistoricalAwards=false
关键词：
Evolution South Pacific Oxygen Preformed

项目摘要

Oxygen concentrations in the deep ocean, in combination with measurements of nutrients and seawater temperature, provide a powerful constraint for the understanding cycling of carbon in the ocean and the amount of atmospheric carbon dioxide. This research uses deep sea sediment cores as recorders of changes in these key environmental variables since the peak of the last ice age, a period encompassing a fundamental shift in the Earth's climate system. Funding supports training of a graduate student, along with a K-12 teacher and two of her high school students. The training activities will also include the participation of members of under-represented groups who have demonstrated interest in the Ocean Sciences. The data will be made available to the community and will be of broad interest to those seeking to understand the cycling of carbon in the ocean.More specifically, this research will further develop a promising method for the quantitative reconstruction of oxygen in the deep ocean-- the difference between carbon isotope values of epibenthic and deep infaunal foraminifera (Dd13C). Using this technique, the research team will generate records of oxygen concentrations in the South Pacific over the last 25,000 years. This time period covers a major climatic transition when atmospheric carbon dioxide concentrations rose from the low levels of glacial times to the higher values of the pre-industrial present. Estimates bottom water phosphate (using Cd/Ca in benthic foraminifera) and bottom water temperature (using Mg/Ca and Li/Ca in benthic foraminifera) will be made using in the same sediment cores. Combined with the oxygen reconstructions, phosphate and temperature information will be used to estimate the nutrient content in the regions where the deep water left the surface (preformed nutrients). The timing and magnitude of the changes in oxygen and preformed nutrients will help to understand how changes in ocean biology and circulation contributed to the lowering in carbon dioxide during the last ice age.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.

深海中的氧气浓度，再加上对营养物和海水温度的测量，为理解海洋中的碳循环和大气中二氧化碳的数量提供了有力的限制。这项研究使用深海沉积物岩心作为自上一次冰河时代高峰以来这些关键环境变量变化的记录器，这一时期涵盖了地球气候系统的根本转变。资金支持培训一名研究生，沿着还有一名K-12教师和她的两名高中学生。培训活动还将包括对海洋科学感兴趣的代表人数不足的团体成员的参与。这些数据将提供给社区，并将引起那些寻求了解海洋碳循环的人的广泛兴趣，更具体地说，这项研究将进一步发展一种有前途的方法，用于定量重建深海中的氧气-海底和深层底栖有孔虫的碳同位素值之间的差异（Dd 13 C）。利用这项技术，研究小组将生成过去25,000年来南太平洋氧气浓度的记录。这一时期涵盖了一个重大的气候转变，大气中的二氧化碳浓度从冰川时代的低水平上升到工业化前的高水平。将使用相同的沉积物岩心估算底层水磷酸盐（使用底栖有孔虫中的Cd/Ca）和底层水温度（使用底栖有孔虫中的Mg/Ca和Li/Ca）。结合氧重建，磷酸盐和温度信息将被用来估计在深水离开表面的区域的营养盐含量（预制营养盐）。氧气和预制营养物变化的时间和幅度将有助于了解海洋生物学和循环的变化如何在最后一个冰河时期有助于降低二氧化碳。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。