华南晚泥盆世底栖与浮游介形类对F-F事件的响应差异及其致因

The proposal focuses on the systematic palaeontology of ostracod fossils during the Late Devonian Frasnian-Famennian (F-F) transition from the selected sections with different palaeogeographical contexts and across facies in South China. This proposal aims to establish the spatio-temporal distribution framework of ostracod faunas of the Upper Devonian in South China and renew the ecological modes of the Devonian ostracods. Taking full advantage of the wide spatial-temporal distribution and sensitivity to environmental changes of ostracods, this proposal intends to reveal the extinction patterns of benthic and pelagic ostracods, and their response to the changes of palaeoenvironmental factors, such as oxygen content, sea level and temperature, by means of the abundance and diversity fluctuations of ostracod faunas in varied palaeoenvironments. Additional background materials associated with sedimentology and sedimentary geochemistry, as well as other fossil evidences will also be taken into consideration. The proposal is of great scientific significance and application prospects as it will serve not only to fill the gap of palaeoecological model of ostracods in the Frasnian-Famennian boundary, but also to provide a new research strategy for probing into the enigmatic cause for the F-F event. Further, it may help to deepen our understanding of the causes of contemporary biodiversity crises in the light of bio-environmental interactions from Paleozoic analogies.

选取华南晚泥盆世弗拉期-法门期（F-F）之交不同古地理位置、跨相区的代表性剖面，以介形类系统古生物学为基础，构建华南晚泥盆世介形类动物群的时空分布格架，更新泥盆纪介形类生态组合模式。充分利用介形类时空分布的广泛性和对环境变化的敏感性，以F-F之交不同沉积环境中介形类动物群的组合特点和丰度、分异度变化为切入点，结合沉积学、沉积地球化学背景资料和其它生物门类的情况，对比探讨底栖和浮游介形类在F-F事件中的灭绝模式和特点，及其对该时期古海洋环境（氧含量、海平面变化、温度等）变化的响应。该研究将有助于填补F-F之交介形类生态模式的空白，为揭示F-F生物环境事件的成因机制提供新资料和新认识，同时对深刻认识当今生物多样性危机具有重要的启示意义。

发生于晚泥盆世弗拉期（Frasnian）-法门期（Famennian）之交的生物环境事件（F-F事件） 是显生宙五大生物灭绝事件之一。本项目选取华南晚泥盆世弗拉期-法门期（F-F）之交不同古地理位置、跨相区的3条代表性剖面，以介形类系统古生物学为基础，构建了华南晚泥盆世介形类动物群的时空分布格架。充分利用介形类时空分布的广泛性和对环境变化的敏感性，以F-F之交不同沉积环境中介形类动物群的组合特点和丰度、分异度变化为切入点，发现了底栖和浮游介形类在F-F事件中不同的灭绝模式和特点：随着水深加大，底栖介形类受到事件影响的程度逐步降低，即浅水底栖介形类灭绝率最高，深水环境中的底栖介形类却没有受到明显影响，但造成了浮游介形类恩托莫介类谱系的缺失。底栖介形类对海水氧气含量、温度变化有积极响应，严重缺氧和快速的温度波动会导致底栖介形类丰度、分异度降低，大部分属种消失。且F-F事件中存在滤食性介形类比率（ff%）增高的“FFS”现象。该研究为揭示F-F生物环境事件的成因机制提供新资料和新认识，对深刻认识当今生物多样性危机具有重要的启示意义。