The Cretaceous/Tertiary Boundary: Deep-sea Benthic Foraminifera and the Cceanic Carbon Cycle

白垩纪/第三纪边界：深海底栖有孔虫和新纪元碳循环

• 批准号: 0720049
• 负责人: Ellen Thomas
• 金额: $ 25万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-15 至 2011-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0720049&HistoricalAwards=false
• 关键词: Cretaceous; Tertiary; Boundary; Deep; sea

This proposal seeks to investigate whether the generally accepted concept of collapse of primary productivity or the biotic pump at the Cretaceous/Tertiary extinction boundary can be supported. The hypothesis poses the question 'Why do deep-sea benthic foraminifera, which were one of the few groups of organisms that provides information on deep-sea ecosystems, not show significant extinction and only relatively minor transient changes given that these organisms rely on a flux of organic matter from the surface to survive'? The proposal hypothesizes that the carbon isotope record across the extinction may not be well understood and be much more complex than generally accepted. Furthermore, the record could have components of productivity collapse, addition of (at least in part) isotopically light carbon to the ocean-atmosphere system, and regional upwelling resulting in massive plankton blooms in a highly unstable environment, persisting for several hundred thousands of years. The PI proposes to investigate benthic foraminiferal assemblage composition, diversity and accumulation rates at high time resolution at various depths and in various oceans, and compare these data with carbon isotope gradients, as well as information on the floral composition of nanoplankton and planktonic foraminifera obtained on the same samples, in order to identify regional and global components of the global carbon cycle. The Broader Impacts include the dissemination of information for society to understand and evaluate possible effects of past major environmental disturbances on ocean ecosystems and the use of this information in teaching materials for middle and high school science teachers.

这项建议旨在调查是否普遍接受的概念崩溃的初级生产力或生物泵在白垩纪/第三纪灭绝的边界可以支持。这一假说提出了一个问题：“深海底栖有孔虫是提供深海生态系统信息的少数几类生物之一，为什么它们没有出现重大灭绝，而只是相对较小的短暂变化，因为这些生物依赖于来自表面的有机物质流生存”？该提案假设，整个灭绝过程中的碳同位素记录可能没有得到很好的理解，并且比普遍接受的要复杂得多。此外，该记录可能包括生产力崩溃、（至少部分）同位素轻碳加入海洋-大气系统以及区域性上涌导致高度不稳定环境中的大量浮游生物大量繁殖，持续数十万年。PI建议在不同深度和不同海洋以高时间分辨率调查底栖有孔虫组合的组成、多样性和积累率，并将这些数据与碳同位素梯度以及从相同样本中获得的关于微型浮游生物和浮游有孔虫植物群组成的信息进行比较，以确定全球碳循环的区域和全球组成部分。更广泛的影响包括传播信息，使社会了解和评估过去重大环境扰动对海洋生态系统可能产生的影响，并在中学和高中科学教师的教材中使用这些信息。