Approximately 55 Ma, the Earth experienced a rapid and extreme episode of global warming that was the product of an unusually massive release of carbon into the ocean-atmosphere system. This event, known as the Paleocene Eocene Thermal Maximum (PETM), had far reaching and significant impacts on global marine and terrestrial ecosystems that ranged from mass extinction of deep sea foraminifera to dispersal and subsequent radiation of plants and ungulates. The combination of these climatic and biotic perturbations initiated dramatic changes in the planet's biogeochemical cycles that eventually worked to restore equilibrium to the global carbon cycle. However, the recovery process took nearly 200,000 yrs. We propose a multi-institutional interdisciplinary program to investigate the effects of the Paleocene Eocene Thermal Maximum (PETM) on the global biosphere and coupled biogeochemical cycles of carbon and nutrients. This project will bring together an international team of experts that includes 11 senior investigators from the US, and 5 from Europe, New Zealand, and China. Building on a foundation of existing work, this study will utilize an array of models to determine the coupling of inorganic and organic chemical processes, to evaluate the relative contributions of these processes in sequestering excess carbon, on short and long-time scales. Empirical data representing marine and terrestrial systems will be generated and used to constrain and evaluate model results. We will evaluate and test existing hypotheses concerning the nature of first order effects and feedbacks of the PETM perturbation on the biosphere and coupled biogeochemical cycles. There are many parallels between the events of 55 Ma and the present day in terms of forcing and response. There are also many differences in the structure of biotic communities and the configuration of continents and oceans. Nevertheless, at a fundamental level, biogeochemical systems and the biosphere would have responded much as they do today. As such, the PETM provides a unique and, possibly the only, opportunity to investigate the short and long-term effects of abrupt greenhouse gas induced warming on global environments.
