ECOSYSTEM RECOVERY FOLLOWING THE PERMO-TRIASSIC MASS EXTINCTION

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The Permo-Triassic mass extinction (PTME; c. 252 Ma) was the most catastrophic biotic event of the Phanerozoic with up to 96% of marine animals going extinct. This event was triggered by massive volcanic eruptions which led to a series of environmental cascades in the oceans, such as rapid and extreme greenhouse warming, ocean anoxia and ocean acidification. The PTME had long lasting effects on the evolution of life with current opinions stating that marine ecosystem recovery took anywhere between 5 to 50 million years. It has also been hypothesised that the PTME caused a permanent ecological regime shift in the world's oceans, marking the end of Palaeozoic benthic ecosystems largely made up of sessile suspension feeders and catalysing the "Mesozoic Marine Revolution", a predator-prey arms race which led to increasing levels of ecological complexity. However, previous attempts to quantify the speed and nature of the recovery interval from the PTME have relied upon indirect measures of ecosystem structure and complexity such as compilations of taxonomic vs functional diversity, qualitative interpretations of ecosystem recovery, and attempts at quantifying changes in life habit and evidence of predation intensity through time. However, to thoroughly test such hypotheses, analyses need to be conducted within a whole ecosystem framework which make use of community ecology methods in order to model ecosystem structural changes via trophic networks (i.e. food webs) through the recovery interval and beyond. This project will explore a novel approach to pushing the frontiers of palaeobiological research via interdisciplinary methods combining recent advances in ecological modelling with palaeontology. Specifically, we will test how marine ecosystems recovered from the PTME and whether this biotic crisis truly represented the beginning of the origins of modern marine ecosystem structure. We will use the rich marine fossil record from South China to model community structure across the PTME and long recovery interval through the Triassic whilst accounting for preservation bias in the fossil record. We will then use the Paleo Foodweb Inference Model to build food webs from ecological traits easily identifiable from the fossil record and then track community structure and function across the PTME and into the recovery interval in the Triassic. This analysis will provide the most precise analysis of how the largest mass extinction in Earth history altered marine ecosystem structure and whether this event heralded the onset of the Mesozoic Marine Revolution and the origins of modern marine ecosystem structure.