Testing geochemical proxy relationships under variable paleo-seawater chemical compositions

代用品在古海洋学重建中的应用依赖于可能对海洋化学变化（例如元素丰度、同位素组成）敏感的校准。这个项目由哥伦比亚大学拉蒙特·多尔蒂地球观测站的一名教员领导，将测试一个假设，即随着海洋化学物质随时间的变化，古代用物的灵敏度保持不变。浮游有孔虫是一种常见的古代用档案，将在实验室中在一系列海水化学物质下进行培养，这些海水化学物质代表了始新世到白垩纪（距今约5000万到1亿年前）海洋条件的变化。这些变化条件的影响将通过几种代用物进行评估，包括稳定的氧和碳同位素以及海水碳酸盐化学的B/Ca代用物。补充研究将研究共生藻类的关联和光合活性，这也会影响有孔虫壳中的化学代理成分。这项研究将提高我们量化过去海洋和气候变化的能力，从而了解未来变化的可能性。资金支持各种教育、外展和服务活动。来自美国的一名研究生和一名本科生将参与该项目，来自澳大利亚的两名研究生也将做出贡献。此外，两名来自纽约市东哈莱姆青年妇女领导学校的高中生也将参加这个培养项目。

The application of proxies to paleoceanographic reconstructions relies on calibrations that may be sensitive to changes in the ocean's chemistry (e.g., elemental abundances, isotopic composition). This project, led by a faculty member at Columbia University's Lamont Doherty Earth Observatory, will test the assumption that the sensitivity of paleo-proxies has remained constant as ocean chemistry has changed over time. Planktonic foraminifera, a common paleo-proxy archive, will be cultured in the laboratory under a range of seawater chemistries representing changing ocean conditions from the Eocene to the Cretaceous (~50 to 100 million years before present). The effects of these changing conditions will be assessed for several proxies, including stable oxygen and carbon isotopes and the B/Ca proxy for seawater carbonate chemistry. Complementary studies will examine the association and photosynthetic activity of symbiotic algae, which also affect chemical proxy composition in foraminifera shells. This research will advance our capacity to quantify past changes in ocean and climate, and thereby to understand potential for future changes. Funding supports a variety of education, outreach, and service activities. One graduate and one undergraduate student from the U.S. will be involved in the project, and two graduate students from Australia will also contribute. In addition, two high school students from the Young Women's Leadership School in East Harlem, New York City, will participate in the culturing program.