重大地质突变期生物与环境事件的分子化石记录

Molecular fossil records as a proxy of the biotic and environmental events during critical geological periods

随着现代分析测试技术的发展,地质类脂物分子在地球环境和生命过程领域得到了快速的应用。总结了志留纪/奥陶纪、晚泥盆世弗拉期/法门期、三叠纪/二叠纪、侏罗纪/三叠纪、古近纪/白垩纪5次生物集群灭绝期地质类脂物分子记录的生物和环境事件。重点讨论了地质类脂物记录的绿硫细菌和水体透光带富硫化氢事件、甲烷菌与海底天然气水合物释放以及这些事件与生物危机的可能关系。提出了当前的工作应从生物危机向生态危机深入,既能反映生物事件与环境事件的关系,又能体现地质记录和地质过程的结合,这其中,地微生物生态系和陆地生态系工作亟待加强。

Geolipids, identifiable by using modern techniques such as gas chromatography （GC） and GC-mass spectrometry, are widely used to understand the history and evolution of life and related earth environments. Here we review the biotic and environmental events by examining the geolipid records in association with the 5 faunal mass extinctions in Phanerozoic, including Silurian/Ordovician, Frasnian/Famenian （late Devonian）, Triassic/Permian, Jurassic/Triassic and Paleogene/Cretaceous. In particular, the occurrence of green sulfur bacteria, methanogens and their associated environmental conditions including the photic zone euxinia and the release of sea floor gas hydrates, are discussed in detail on the basis of geolipids such as acyl isoprenoids, crocetane and 3-methylhopanes during the five biotic crisis. We propose that further studies of ecological crisis instead of the biotic crisis are necessary, with the emphasis on integrating data from organisms and the associated environmental conditions, the geological records and the underlying processes. More attention should be given to geomicrobial ecology and terrestrial ecology.