The early Mesozoic (Permian/Triassic boundary to mid-Jurassic) was a critical time in the evolution of life on Earth, and understanding this interval of time is central to understanding the subsequent evolution of the marine biosphere. The earliest Triassic was a time of significant global warming and records the immediate aftermath of the most severe biodiversity loss of the Phanerozoic. The subsequent recovery, as climate ameliorated through the Triassic, was curtailed by another major extinction event in the latest Triassic, associated with an increase in atmospheric carbon dioxide levels, global warming and possible ocean acidification. Recovery in the earliest Jurassic was more rapid than that of the Early Triassic, but was affected by another episode of global warming and oceanic anoxia in the Toarcian. This project aims to understand the responses of the marine ecosystem to these past episodes of major global warming, including analyses of global, regional and local biodiversity loss and recovery. A key aim of this project will be the isotopic analysis of brachiopod shell material to provide the first quantitative palaeotemperature curve of the early Mesozoic. This will be combined with the morphometric and biodiversity analyses to assess how episodes of major global warming directly affect marine invertebrate groups. Ecosystem-level changes associated with global warming and anoxia will be evaluated. These data are to crucial to the evalaution of predicted ecosystem response to present day global warming and marine hypoxia.