Chlorophyll dN-15: An Isotopic Benchmark for Understanding N Cycling and Paleochemistry in the Mediterranean Sea

叶绿素 dN-15：了解地中海氮循环和古化学的同位素基准

• 批准号: 9711702
• 负责人: Daniel Repeta
• 金额: $ 39.7万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-15 至 2001-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9711702&HistoricalAwards=false
• 关键词: Chlorophyll; dN; 15; Isotopic; Benchmark

Repet702 ABSTRACT Recent reports of nitrogen distribution in marine sediments offer the exciting prospect of tracking changes in the marine nitrogen cycle through time, including changes in paleoproductivity and paleonitrification. These developments show great promise in adding to our understanding of large-scale controls on marine production, carbon preservation in sediments, and the interplay between climate and geochemical cycling. In this project, the principal investigator will focus attention on the main impediment to using sedimentary nitrogen isotopes in paleo- oceanographic studies: namely, the large and non-quantifiable imprint of early diagenesis on the sedimentary N15 record. Specifically he will continue his studies of the N15 composition of sedimentary chlorophyll-a as a tracer for processes affecting surface water nutrient dynamics. This approach should be more reliable that using N15 for bulk sedimentary organic matter in which the N15 signature of surface conditions is convoluted with post-depositional changes in nitrogen chemistry since deposition at the sediment surface.

Repet702 摘要 最近关于海洋沉积物中氮分布的报告为跟踪海洋氮循环随时间的变化（包括古生产力和古硝化作用的变化）提供了令人兴奋的前景。 这些进展显示出巨大的前景，有助于增强我们对大规模海洋生产控制、沉积物碳保存以及气候与地球化学循环之间相互作用的理解。 在本项目中，主要研究人员将重点关注在古海洋学研究中使用沉积氮同位素的主要障碍：即早期成岩作用在沉积物 N15 记录中留下的巨大且不可量化的印记。 具体来说，他将继续研究沉积叶绿素-a 的 N15 组成，作为影响地表水营养动态过程的示踪剂。 这种方法应该比使用 N15 来处理大量沉积有机物更可靠，其中表面条件的 N15 特征与沉积物表面沉积后氮化学的沉积后变化相结合。