Testing geochemical proxy relationships under variable paleo-seawater chemical compositions

代用指标在古海洋学重建中的应用依赖于可能对海洋化学变化敏感的校准（例如，元素丰度、同位素组成）。该项目由哥伦比亚大学拉蒙多尔蒂地球观测站的一名教员领导，将测试一个假设，即随着海洋化学随时间的推移而变化，古代理的敏感性保持不变。浮游有孔虫是一种常见的古代用品档案，将在实验室中培养，在一系列海水化学条件下，代表从始新世到白垩纪（距今约5000万至1亿年）不断变化的海洋条件。这些不断变化的条件的影响将评估几个代理，包括稳定的氧和碳同位素和海水碳酸盐化学的B/Ca代理。补充研究将检查共生藻类的关联和光合作用活性，这也影响有孔虫壳的化学代用品组成。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潜力。资金支持各种教育，推广和服务活动。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，来自纽约市东哈莱姆青年妇女领导学校的两名高中生将参加培养计划。

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.