ECOSYSTEM RECOVERY FOLLOWING THE PERMO-TRIASSIC MASS EXTINCTION

二叠纪-三叠纪大灭绝(PTME；约252 Ma)是显生界最灾难性的生物事件，高达96%的海洋动物灭绝。这一事件是由大规模火山喷发引发的，导致了一系列海洋环境级联，如迅速和极端的温室效应、海洋缺氧和海洋酸化。PTME对生命的进化产生了长期持久的影响，目前的观点认为，海洋生态系统的恢复需要500万到5000万年的时间。还有人假设，临时海洋生态系统引起了世界海洋生态制度的永久性转变，标志着主要由固着悬浮摄食者组成的古生代底栖生态系统的终结，并催化了“中生代海洋革命”，这是一场捕食者-被捕食者的军备竞赛，导致了生态复杂性的增加。然而，以前对临时生态系统恢复间隔的速度和性质进行量化的尝试依赖于对生态系统结构和复杂性的间接测量，例如分类多样性与功能多样性的汇编、对生态系统恢复的定性解释，以及试图量化生活习惯的变化和捕食强度随时间的证据。然而，为了彻底检验这些假说，需要在利用群落生态学方法的整个生态系统框架内进行分析，以便通过营养网络(即食物网)模拟整个恢复间隔期及以后的生态系统结构变化。该项目将探索一种新的方法，通过将生态建模方面的最新进展与古生物学相结合的跨学科方法，推动古生物学研究的前沿。具体地说，我们将测试海洋生态系统如何从PTME恢复，以及这场生物危机是否真正代表了现代海洋生态系统结构起源的开始。我们将利用中国南部丰富的海洋化石记录来模拟整个PTME和三叠纪漫长的恢复间隔的群落结构，同时考虑化石记录中的保存偏差。然后，我们将使用古食物网推断模型，从化石记录中容易识别的生态特征建立食物网，然后跟踪整个PTME的群落结构和功能，并进入三叠纪的恢复区间。这一分析将对地球历史上最大规模的大灭绝如何改变海洋生态系统结构以及这一事件是否预示着中生代海洋革命的开始和现代海洋生态系统结构的起源提供最准确的分析。

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.