PAOC Colloquium: Michael Bender (Princeton)

Title: Patchy ice core records of climate and greenhouse gases during 40,000 year climate cycles of the Early Pleistocene

Abstract: A multi-institutional collaboration has retrieved samples of Antarctic ice dating beyond 2 Ma, and analyzed these samples for greenhouse gas concentrations and other climate properties. Interpreting the data is complicated because the samples are stratigraphically disturbed. Nonetheless, the results suggest that interglacial Antarctic temperatures, as well as atmospheric CO2 and CH4 concentrations, are within the ranges observed for the past 800,000 years. None of our old ice samples have temperatures or greenhouse gas concentrations as low as glacial values of the past 800,000 years. The data suggest some simple speculations about the dynamics of Pleistocene climates.

About the Speaker

Michael Bender received a BS in Chemistry from Carnegie-Mellon University, where he was introduced to geochemistry by Truman Kohman. He did his PhD in Geology at Columbia University with Wallace Broecker. After a brief postdoc, he moved to the Graduate School of Oceanography, University of Rhode Island, where he taught for 25 years. In 1997, he moved to Princeton.

Bender's research has centered on two themes. One is glacial-interglacial climate change, and the other is the global carbon cycle. Since 1984, Bender's paleoclimate research has involved measuring gas properties in ice cores to date critical climate changes of the ice ages, and to advance our understanding of changes in the biosphere on glacial-interglacial timescales. The carbon cycle research involves studies characterizing the fertility of ecosystems at the global scale, at the scale of ocean basins, and at regional to local scales within the oceans.

Much current work in Bender's lab involves making highly precise measurements of the concentration and isotopic composition of O2 in air, in seawater, and in ice core trapped gases as a means of studying both the geochronology of climate change and the carbon cycle at a range of scales. Bender's past work has also included studies of trace element assimilation by carbonate tests, seawater trace metal geochemistry, hydrothermal processes on the flanks of mid-ocean ridges, diagenesis of organic matter in deep sea sediment pore waters, and the history of the seawater Sr isotope composition.

About this Series

The PAOC Colloquium is a weekly interdisciplinary seminar series that brings together the whole PAOC community. Seminar topics include all research concerning the physics, chemistry, and biology of the atmospheres, oceans and climate, but also talks about e.g. societal impacts of climatic processes. The seminars generally take place on Monday from 12-1pm. Lunch is provided to encourage students and post-docs to meet with the speaker. Besides the seminar and lunch, individual meetings with professors, post-docs, and students are arranged.