Combined X-Ray and Raman Spectroscopic Techniques for the Characterization of Sea Spray Aerosol

Friday, 19 December 2014
Josephine Y Aller1, Peter Aaron Alpert2, Daniel Alexander Knopf2, Wendy Kilthau1, Dylan Bothe1, Joseph C. Charnawskas2, Mary Kathleen Gilles3, Rachel E OBrien3, Ryan Moffet4 and JoAnn Radway1, (1)Stony Brook University, School of Marine and Atmospheric Sciences, Stony Brook, NY, United States, (2)Stony Brook University, Institute for Terrestrial and Planetary Atmospheres / School of Marine and Atmospheric Sciences, Stony Brook, NY, United States, (3)Lawrence Berkeley National Lab, Berkeley, CA, United States, (4)University of the Pacific, Stockton, CA, United States
Sea spray aerosol along with mineral dust dominates the global mass flux of particles to the atmosphere. Marine aerosol particles are of particular interest because of their continual impact on cloud formation, precipitation, atmospheric chemical processes, and thus global climate. Here we report on the physical/chemical characteristics of sub-surface waters, aerosolized sea spray particles, and particles/organic species present in surface microlayer (SML) samples collected during oceanic field campaigns and generated during laboratory experiments, revealing a biogenic primary source of the organic fraction of airborne particles. We also report on ice nucleation experiments with aerosolized particles collected during the May 2014 WACS II North Atlantic cruise and with laboratory generated exudate material from diatom cultures with the potential to impact cirrus and mixed phase clouds. Physicochemical analyses using a multi-modal approach which includes Scanning Transmission X-ray Microscopy coupled with Near-Edge Absorption Fine Structure Spectroscopy (STXM/NEXAFS) and Raman spectroscopy confirm the presence and chemical similarity of polysaccharide-rich transparent exopolymer (TEP) material and proteins in both SML sea spray aerosol and ice forming aerosol particles, regardless of the extent of biological activity in surface waters. Our results demonstrate a direct relationship between the marine environment and composition of marine aerosol through primary particle emission.