Application of a New Method for Isotopic Analysis of Diatom Microfossil-bound Nitrogen

南大洋可能在导致冰河时代和全球总体气候变化方面发挥核心作用。这项工作将揭示冰川海洋的主要特征，并可能通过测量南极海洋沉积物中发现的硅藻化石中某些氮同位素的丰度来解释冰川/间冰期循环的原因。硅藻结合的氮是一个潜在的重要的养分利用记录器。南大洋的营养状况、生产力和环流可能是决定全球大气二氧化碳含量和气候其他方面的核心因素。之前进行这些测量的尝试都产生了模棱两可的结果。该项目包括技术开发和分析，包括对沉积物捕集器和养殖实验中的硅藻进行测量。至于更广泛的影响，这笔助学金的重点是研究生的教育和学术发展，将他们的研究与本科生研究人员的指导相结合。

The Southern Ocean may play a central role in causing ice ages and general global climate change. This work will reveal key characteristics of the glacial ocean, and may explain the cause of glacial/interglacial cycles by measuring the abundances of certain isotopes of nitrogen found in fossil diatoms from Antarctic marine sediments. Diatom-bound N is a potentially important recorder of nutrient utilization. The Southern Ocean's nutrient status, productivity and circulation may be central to setting global atmospheric CO2 contents and other aspects of climate. Previous attempts to make these measurements have yielded ambiguous results. This project includes both technique development and analyses, including measurements on diatoms from both sediment traps and culture experiments. With regard to broader impacts, this grant is focused around the education and academic development of a graduate student, by coupling their research with mentorship of an undergraduate researcher