Predicted and Observed Differences in Organic Functional Group Composition in Marine Aerosols from Three Oceans

Lynn M Russell1, Savannah Lewis1, Georges Saliba2, Robin L. Modini3, Luke T Cravigan4, Zoran Ristovski5, Patricia Quinn6, Timothy S Bates7 and Amanda A Frossard8, (1)University of California San Diego, Scripps Institution of Oceanography, La Jolla, CA, United States, (2)Carnegie Mellon University, Center for Atmospheric Particle Studies, Pittsburgh, PA, United States, (3)EPFL Swiss Federal Institute of Technology Lausanne, Lausanne, Switzerland, (4)Queensland University of Technology, Brisbane, QLD, Australia, (5)Queensland University of Technology, School of Chemistry, Physics and Mechanical Engineering, Brisbane, QLD, Australia, (6)Atmospheric Chemistry Group & TPOS 2020 project, University of Washington/JISAO & NOAA/PMEL, Seattle, WA 98115, Seattle, WA, United States, (7)NOAA PMEL, Seattle, United States, (8)University of Georgia, Department of Chemistry, Athens, United States
The salt content of surface ocean waters is very consistent worldwide, but how consistent is the organic component? And how does that affect the organic component of sea spray? Using Fourier Transform Infrared (FTIR) spectroscopy, the NAAMES, SOAP, and E-PEACE campaigns have characterized the organic functional group composition of ambient submicron aerosol particles during open-ocean sampling in the North Atlantic, the Southern Ocean, and the Northeastern Pacific regions. We expect the ratios and concentrations of these organic functional groups are the result of the ocean biota that consume, process, and release organic carbon, which provide a link to aerosol composition and properties.

Models like OCEANFILMS provide spatial and temporal predictions of the distribution of mixtures of organic components that show the differences that are expected for different oceans at different times of year. For example, the ratio of alkane group mass to alcohol group mass is expected to be highest in late spring in the North Atlantic, which is what was found in the NAAMES measurements. The magnitude of the ratios predicted by OCEANFILMS are more similar to the measured values for the low-lipid, high-polysaccharide simulation. This composition is important because it could also impact the properties of sea spray particles, since organic functional groups affect the surface tension, viscosity, and density of surface water and the microlayer and subsequently the properties of aerosol particles.