9419322 Chavez This proposal was submitted in response to a one-time Program Announcement - NSF 93-101 for the Coastal Ocean Processes (CoOP) Coastal Air-Sea Chemical Fluxes pilot study. The Announcement suggested that a mutually beneficial opportunity exists to coordinate an NSF/CoOP research effort with the ONR-sponsored Marine Boundary Layer (MBL) Advanced Research Initiative (ARI) planned for 1995. The CoOP study might complement the ONR physical processes study by encompassing biological and chemical oceanographic processes aimed at developing a mechanistic understanding of air-sea fluxes. The overall scientific project would be interdisciplinary, with the NSF/CoOP efforts addressing chemical and biological parameters, while the ONR study focuses on physical oceanographic and meteorological parameters. This research is a collaborative effort with the University of Southern California. The work will determine the effect of phytoplankton productivity on the fate of upwelled CO2 in coastal environments. The PIs intend to make measurements of pCO2, TCO2, NO3, NH4, urea, pigments, POC, PON, biogenic silicon (BSi) and Si(OH)4 and also perform incubations with 14CO2, 15NO3, 15NH, and 15N-urea to estimate and interpret biological activities within the region of the experiment. The ultimate goal is to determine how nutrient concentrations control uptake of "new" CO and the length of time that high surface water pCO2 concentrations remain above atmospheric levels. Because the rate of new production controls the length of time newly upwelled CO2 are exposed to the atmosphere, its measurement is key to a thorough understanding of the CO2 flux transfer from ocean to atmosphere. Data collection will be conducted through both underway and station shipboard activities as well as through drifters and moorings. Phytoplankton species determinations will be made on selected samples. Finally, the ratios of uptake of carbon to nitrogen, disappearance of CO2:NO3:Si( OH)4 from the water column, and POC:PON:BSi will be calculated from collected data. The proposed work will be coordinated with physical and meteorological experiments to be conducted by other researchers.
