Collaborative Research: Testing the reduction of aerobic habitat as a common kill mechanism for major mass extinction events

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The project will study the response of marine animal ecosystems to environmental change using three mass extinction events from the geological record as study systems. Specifically, the project will test the hypothesis that a large proportion of extinction during these events can be explained by the stresses that elevated temperatures and reduced oxygen availability place on animal respiration. Geochemical data will be used to constrain computer simulations of changing ocean conditions during these mass extinction events. Results from laboratory studies on animal respiration will then be paired with fossil data to assess whether differences in extinction intensity in space and across taxonomic groups can be explained by spatial variation in environmental change or differences among taxonomic groups in their ability to withstand environmental change. The project will provide interdisciplinary training to a group of graduate students and post-docs. It will further impact STEM education through the creation of a website that will allow access to model results so that students can visualize and explore model output to understand cause-effect relationships between continental configuration, ocean conditions, and biological diversity. The investigators will also offer short-courses on Earth system modeling and data interpretation at major conferences that will be recorded for asynchronous use. The project will also involve the development of a podcast series addressing how we reconstruct the ancient Earth system and use these reconstructions to better understand the present and predict the future.In this project, the hypothesis will be tested that the loss of habitat through constraints on aerobic respiration under climate change and ocean deoxygenation can explain the magnitude, taxonomic selectivity, and latitude variation in intensity for the Late Devonian (Frasnian-Fammenian), end-Permian, and end-Triassic mass extinction events. Paleoredox and paleoclimate proxy data and geochemical indicators of diagenetic alteration will be used for both global average and local conditions before and after each major event combined with predictions from Earth system models and occurrence data from the fossil record of marine animals to separate aspects of extinction than can be explained by physiological stress from those that require other explanations.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.