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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.

深海中的氧气浓度与营养物质和海水温度的测量相结合，为了解海洋中的碳循环和大气中二氧化碳的量提供了强有力的限制。这项研究利用深海沉积物岩心作为自上一个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。资金用于支持一名研究生、一名 K-12 教师和两名高中生的培训。培训活动还将包括对海洋科学表现出兴趣的代表性不足群体的成员的参与。这些数据将向社会公开，并引起那些寻求了解海洋碳循环的人们的广泛兴趣。更具体地说，这项研究将进一步开发一种有前途的方法来定量重建深海中的氧气——表底栖动物和深部动物有孔虫碳同位素值（Dd13C）之间的差异。利用这项技术，研究小组将生成过去 25,000 年南太平洋氧气浓度的记录。这一时期涵盖了一个主要的气候转变，当时大气中的二氧化碳浓度从冰河时代的低水平上升到工业化前的较高水平。估算底水磷酸盐（使用底栖有孔虫中的 Cd/Ca）和底水温度（使用底栖有孔虫中的 Mg/Ca 和 Li/Ca）将在相同的沉积物岩心中进行。结合氧气重建、磷酸盐和温度信息，将用于估计深水离开表面的区域的营养物含量（预先形成的营养物）。氧气和预先形成的营养物质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导致上一个冰河时期二氧化碳的减少。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。