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

本研究旨在探讨白垩纪/第三纪灭绝边界的初级生产力崩溃或生物泵的普遍接受的概念是否可以得到支持。这一假说提出了这样一个问题：“深海底栖有孔虫是为数不多的提供深海生态系统信息的生物之一，鉴于这些生物依赖于来自表面的有机物质的流动而生存，为什么它们没有出现重大的灭绝，只有相对较小的短暂变化？”该提议假设，在大灭绝期间的碳同位素记录可能没有得到很好的理解，而且比普遍接受的要复杂得多。此外，这一记录可能包括生产力崩溃的组成部分，向海洋-大气系统添加（至少部分）同位素轻碳，以及在高度不稳定的环境中导致大量浮游生物大量繁殖的区域上升流，持续了数十万年。该项目拟在不同深度和不同海洋进行高时间分辨率的底栖有孔虫组合组成、多样性和积累速率研究，并将这些数据与碳同位素梯度以及在相同样品上获得的纳米浮游生物和浮游有孔虫的植物组成信息进行比较，以确定全球碳循环的区域和全球组成。更广泛的影响包括传播信息，使社会了解和评价过去重大环境干扰对海洋生态系统可能产生的影响，并将这些信息用于初中和高中科学教师的教材中。

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.