Field Measurements of Trace Gas Reactions at the Air-Ocean Interface

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This project focuses on the emission of reactive gases from the surface of the ocean. It is well known that marine phytoplankton and bacteria produce a wide array of reactive gases that are subsequently emitted to the atmosphere. Recent laboratory experiments have suggested that chemical and photochemical reactions at the surface of the ocean may also produce significant quantities of reactive gases. This project is designed to determine both the sea-to-air emission rate of a wide array of reactive gases and the dominant production mechanisms for these molecules in seawater. This research will provide new, quantitative insight on the impact of marine reactive gas emissions on oxidant concentrations and the production rate of secondary organic aerosol particles. The specific objectives of this research are: (1) to measure the air-sea flux of oxygenated volatile organic compounds (oVOCs), (2) to partition the observed flux between biochemical, photochemical, and heterogeneous reaction pathways using in field measurements of oVOC emission rates from collected seawater, and (3) to determine that factors that control the emission rate and production pathways for oVOC production at the air-sea interface. To carry out these objectives we will make new measurements of the air-sea flux of oVOCs and ozone via eddy covariance alongside flow reactor measurements of oVOC emission from collected seawater as a function of light intensity and oxidant exposure. The work here will make up the larger part of the Ph.D. theses for two chemistry graduate students at University of Wisconsin (UW) Madison. Elements of the field work will serve as the foundation for multiple UW Madison undergraduate independent research projects. This project will also permit the continued involvement of the Principal Investigator (PI) and Ph.D. students in education and outreach activities that bring small sensor technology to high school classrooms around the state of Wisconsin.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.