Award: OCE-0961653

Project Outcomes Report (NSF 0961653; 2009-14) Intellectual Merit This project is a collaborative between University of Delaware (Church), Queens College SUNY (Stewart) and Wayne State University (Baskaran). The subject is on the distribution and exchange of the 210-Po/210-Pb nuclide pair across major oceanic interfaces on a basin wide scale. Studies of this complexity and magnitude have not been done for decades and never in this detail. The goal is to provide accurate and quantitative tracers for a host of surrogate trace element isotopes. The findings reveal significant details related to carbon and particle transfer from the surface to the deep sea within the North Atlantic Ocean basins, and across key interfaces near the coast, the bottom layers and a hydrothermal plume. As such, polonium proves to be an intimately timed tracer for biogenic material, and by proxy that of oceanic carbon uptake, flux and benthic regeneration. This is a major component of the global carbon budget and thus climatically important carbon dioxide. Broader Impacts Support has been provided for research with the participation of undergraduate and graduate students on subjects central to the proposed research. Specifically, two postdoctoral fellows, three graduate and two undergraduate students have been trained in the processing and analysis of the natural 210-Po/210-Pb pair. They have been educated in model application to oceanic and estuarine carbon dynamics and processing of trace elements by isotopic proxy. One was a Latino student who was awarded a National Science Foundation-Bridge to the Doctorate Research Fellowship for granting of a Masters degree. Key aspects of the research have been used for student presentations to professional meetings, and in courses by the principle investigator on oceanography, isotopic geochemistry and environmental chemistry. Last Modified: 06/18/2014 Submitted by: Thomas M Church