title: Microbial Control of Sea Spray Aerosol Composition: A Tale of Two Blooms.
abstract: With the oceans covering 71% of the Earth, sea spray aerosol (SSA) particles profoundly impact climate through their ability to scatter solar radiation and serve as seeds for cloud formation. The climate properties can change when sea salt particles become mixed with insoluble organic material formed in ocean regions with phytoplankton blooms. Currently, the extent to which SSA chemical composition and climate properties are altered by biological processes in the ocean is uncertain. To better understand the factors controlling SSA composition, we carried out a mesocosm study in an isolated ocean-atmosphere facility containing 3,400 gallons of natural seawater. Over the course of the study, two successive phytoplankton blooms resulted in SSA with vastly different composition and properties. During the first bloom, aliphatic-rich organics were enhanced in submicron SSA and tracked the abundance of phytoplankton as indicated by chlorophyll-a concentrations. In contrast, the second bloom showed no enhancement of organic species in submicron particles. A concurrent increase in ice nucleating SSA particles was also observed only during the first bloom. Analysis of the temporal variability in the concentration of aliphatic-rich organic species, using a kinetic model, suggests that the observed enhancement in SSA organic content is set by a delicate balance between the rate of phytoplankton primary production of labile lipids and enzymatic induced degradation. This study establishes a mechanistic framework indicating that biological processes in the ocean and SSA chemical composition are coupled not simply by ocean chlorophyll-a concentrations, but are modulated by microbial degradation processes. This work provides unique insight into the biological, chemical, and physical processes that control SSA chemical composition, that when properly accounted for may explain the observed differences in SSA composition between field studies.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Camille M
authors.initials: CM
authors.lastname: Sultana
authors.affiliation: Department of Chemistry, University of Iowa , Iowa City, Iowa 52242, United States.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Trueblood
authors.affiliation: Department of Atmospheric Science, Colorado State University , Fort Collins, Colorado 80523, United States.
authors.forename: Thomas C J
authors.initials: TC
authors.lastname: Hill
authors.affiliation: Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093, United States; National Institute of Oceanography and Experimental Geophysics, Trieste 34100, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Malfatti
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Christopher
authors.initials: C
authors.lastname: Lee
authors.affiliation: Department of Chemistry, University of Iowa , Iowa City, Iowa 52242, United States.
authors.forename: Olga
authors.initials: O
authors.lastname: Laskina
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Moore
authors.affiliation: Scripps Institution of Oceanography, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Charlotte M
authors.initials: CM
authors.lastname: Beall
authors.affiliation: Department of Atmospheric Science, Colorado State University , Fort Collins, Colorado 80523, United States.
authors.forename: Christina S
authors.initials: CS
authors.lastname: McCluskey
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Gavin C
authors.initials: GC
authors.lastname: Cornwell
authors.affiliation: Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093, United States; State Key Laboratory of Marine Environmental Science and Key Laboratory of the MOE for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361005, P. R. China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Joshua L
authors.initials: JL
authors.lastname: Cox
authors.affiliation: Scripps Institution of Oceanography, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Pendergraft
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Mitchell V
authors.initials: MV
authors.lastname: Santander
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.
authors.forename: Timothy H
authors.initials: TH
authors.lastname: Bertram
authors.affiliation: Department of Civil and Environmental Engineering, University of California, Davis , Davis, California 95616, United States.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Cappa
authors.affiliation: Scripps Institution of Oceanography, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Farooq
authors.initials: F
authors.lastname: Azam
authors.affiliation: Department of Atmospheric Science, Colorado State University , Fort Collins, Colorado 80523, United States.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: DeMott
authors.affiliation: Department of Chemistry, University of Iowa , Iowa City, Iowa 52242, United States.
authors.forename: Vicki H
authors.initials: VH
authors.lastname: Grassian
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States; Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Prather