Characterization of early Eocene hyperthermals using benthic foraminiferal assemblages and stable isotopes

The aim of this project is to evaluate the short-and long-term effects of multiple subsequent global warming events on the marine biosphere in the earliest Eocene, about 56 to 52 million years ago (Ma). By studying the response of ecosystems to these transient warming events, or hyperthermals, an assessment of biogeosphere dynamics in an early Eocene greenhouse world setting can be made. More specifically, the objective is to improve our understanding of the response of deep-sea benthic ecosystems to hyperthermals using foraminiferal assemblages and stable carbon and oxygen isotopes (δ13C and δ18O). Deep-sea benthic communities may track changes in temperature, ocean circulation and stratification, pH and organic fluxes, and thus reflect the environmental changes during the non-catastrophic Eocene Thermal Maximum 2 (ETM2; ~54 Ma) hyperthermal. In the context with the (semi-) catastrophic effects of the Paleocene-Eocene Thermal Maximum (PETM; ~56 Ma), this study provides additional tiepoints in the assessment of benthic ecosystem sensitivity. Although the Eocene greenhouse world differs significantly from the present day in a number of ways (e.g. continent configuration and mountain ranges, ocean circulation, atmospheric CO2 concentrations and latitudinal global temperature gradients), this research is still relevant in the debate on anthropogenic global warming, as it may show how (in)sensitive the marine biosphere is to abrupt global warming.nrpages: 227status: publishe