Talk Title:  The Evolution of the Marine Carbonate Factory and the Rise of Biomineralizing Animals

Abstract: Formation of calcium carbonate is one of the primary pathways by which carbon is recycled between the ocean-atmosphere system and the solid Earth. On long timescales, changes in the magnitude of the marine carbonate factory—the precipitation and distribution of carbonate minerals in marine settings—are tied to weathering. The carbonate factory, in turn, plays a critical role in shaping marine biogeochemical cycling and in modulating atmospheric CO2 concentrations. A paucity of empirical constraints on the scale and pace of these processes has led to widely divergent views on how the marine carbonate factory has changed through time. I will present data generated using an emerging proxy, the stable strontium isotope system, to provide new insights into the long-term evolution of the marine carbonate factory over the past three billion years of Earth’s history. Our compilation suggests that key components of the carbonate factory were directly shaped by the rise of biomineralizing organisms. Additionally, these data suggest that reservoirs outside of the traditional shallow-marine carbonate factory—such as porewater production of authigenic carbonates—must have represented a major carbon burial sink through much of this interval and may hold important implications for Earth’s paleoclimate evolution.

Short Bio: Dr. Lidya Tarhan is an Assistant Professor in the Department of Earth and Planetary Sciences at Yale University and an Assistant Curator of Invertebrate Paleontology at the Yale Peabody Museum. Her research focuses on using the sedimentary record to reconstruct the co-evolution of ancient life and environments during critical intervals of Earth’s history. She also investigates the processes responsible for fossilization and how preservational biases modify stratigraphic and geobiological archives. She combines field-based paleontological and sedimentological investigations with a geochemical, petrographic and modeling toolkit. Her recent work has centered on reconstructing the emergence of early animals as ecosystem engineers. In addition to her geologic investigations, she also studies the environmental factors shaping animal-sediment interactions in modern marine settings.

Webpage: http://campuspress.yale.edu/lidyatarhan/

To be added to the EPS colloquium mailing list, please contact Maryorie Grande (grande@eps.harvard.edu)