|Title||Bringing the ocean into the laboratory to probe the chemical complexity of sea spray aerosol|
|Publication Type||Journal Article|
|Year of Publication||2013|
|Authors||Prather KA, Bertram TH, Grassian VH, Deane GB, Stokes MD, DeMott PJ, Aluwihare LI, Palenik BP, Azam F, Seinfeld JH, Moffet RC, Molina MJ, Cappa CD, Geiger FM, Roberts GC, Russell LM, Ault AP, Baltrusaitis J, Collins DB, Corrigan CE, Cuadra-Rodriguez LA, Ebben CJ, Forestieri SD, Guasco TL, Hersey SP, Kim MJ, Lambert WF, Modini RL, Mui W, Pedler BE, Ruppel MJ, Ryder OS, Schoepp NG, Sullivan RC, Zhao DF|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Type of Article||Article|
|Keywords||atmosphere; biologically active; breaking waves; bubble; cloud condensation nuclei; Clouds; dissolved organic-matter; enrichment; ice nucleation; ice nuclei; in-situ; marine aerosols; primary marine aerosol; salt; surface microlayer|
The production, size, and chemical composition of sea spray aerosol (SSA) particles strongly depend on seawater chemistry, which is controlled by physical, chemical, and biological processes. Despite decades of studies in marine environments, a direct relationship has yet to be established between ocean biology and the physicochemical properties of SSA. The ability to establish such relationships is hindered by the fact that SSA measurements are typically dominated by overwhelming background aerosol concentrations even in remote marine environments. Herein, we describe a newly developed approach for reproducing the chemical complexity of SSA in a laboratory setting, comprising a unique ocean-atmosphere facility equipped with actual breaking waves. A mesocosm experiment was performed in natural seawater, using controlled phytoplankton and heterotrophic bacteria concentrations, which showed SSA size and chemical mixing state are acutely sensitive to the aerosol production mechanism, as well as to the type of biological species present. The largest reduction in the hygroscopicity of SSA occurred as heterotrophic bacteria concentrations increased, whereas phytoplankton and chlorophyll-a concentrations decreased, directly corresponding to a change in mixing state in the smallest (60-180 nm) size range. Using this newly developed approach to generate realistic SSA, systematic studies can now be performed to advance our fundamental understanding of the impact of ocean biology on SSA chemical mixing state, heterogeneous reactivity, and the resulting climate-relevant properties.