A11D-0088
Comparing Organic Aerosol Composition from Marine Biogenic Sources to Seawater and to Physical Sea Spray Models
Monday, 14 December 2015
Poster Hall (Moscone South)
Lynn M Russell1, Amanda Ann Frossard2, Kevin Sanchez1, Paola Massoli3, Scott Elliott4, Susannah M Burrows5, Timothy S Bates6 and Patricia Quinn7, (1)Scripps/UCSD, La Jolla, CA, United States, (2)University of California Berkeley, Berkeley, CA, United States, (3)Aerodyne Research Inc., Billerica, MA, United States, (4)Los Alamos National Laboratory, Los Alamos, NM, United States, (5)Pacific Northwest National Laboratory, Richland, WA, United States, (6)University of Washington Seattle Campus, Seattle, WA, United States, (7)NOAA Pacific Marine Environmental Laboratory, Seattle, WA, United States
Abstract:
In much of the marine atmosphere, organic components in aerosol particles have many sources other than sea spray that contribute organic constituents. For this reason, physical sea spray models provide an important technique for studying the organic composition of particles from marine biogenic sources. The organic composition of particles produced by two different physical sea spray models were measured in three open ocean seawater types: (i) Coastal California in the northeastern Pacific, which is influenced by wind-driven, large-scale upwelling leading to productive or eutrophic (nutrient-rich) seawater and high chl-a concentrations, (ii) George’s Bank in the northwestern Atlantic, which is also influenced by nutrient upwelling and eutrophic seawater with phytoplankton productivity and high chl-a concentrations, and (iii) the Sargasso Sea in the subtropical western Atlantic, which is oligotrophic and nutrient-limited, reflected in low phytoplankton productivity and low chl-a concentrations. Fourier transform infrared spectroscopy provides information about the functional group composition that represents the marine organic fraction more completely than is possible with techniques that measure non-refractory mass (vaporizable at 650°C). After separating biogenic marine particles from those from other sources, the measured compositions of atmospheric marine aerosol particles from three ocean regions is 65±12% hydroxyl, 21±9% alkane, 6±6% amine, and 7±8% carboxylic acid functional groups. The organic composition of atmospheric primary marine (ocean-derived) aerosol particles is nearly identical to model generated primary marine aerosol particles from bubbled seawater. Variability in productive and non-productive seawater may be caused by the presence of surfactants that can stabilize the bubble film and lead to preferential drainage of the more soluble (lower alkane group fraction) organic components without substantial changes in overall group composition. There is sparse evidence for the size dependence of organic aerosol particle composition from marine biogenic sources, which could provide an important mechanistic link to sea spray production.
