The end-Permian biotic crisis
The end-Permian crisis (250 My ago) is long known for its impact on marine ecosystems. There is still animated discussion on the cause of the end-Permian crisis. The proposed concepts differ with respect to source (extraterrestrial or terrestrial) and rate (catastrophic to relatively rapid). Several terrestrial-bound scenarios have been proposed to explain the end Permian crisis. These involve worldwide oceanographic and/or atmospheric perturbations, which also are associated with the present-day ecological crisis, such as increasing CO2 levels, ozone reduction, acid rain, temperature changes, sea level changes and oceanic anoxia. To understand certain aspects of the complex nature of the Permian-Triassic event we used an interdisciplinary approach, combining biostratigraphy, geochemistry (organic and stable isotopes), with palynology and paleobotany. I collaborated with colleagues from Utrecht University, Mark Sephton (Imperial College London, see figure), Richard Twitchett (Plymouth University), Kliti Grice (Curtin University of Technology, Perth) and Jonathan Watson (Open University, Milton Keynes) on the following projects.