The oceans, atmosphere, and clouds are all interconnected through the release and deposition of chemical species, which provide critical feedback in controlling the composition of our atmosphere and climate. To better understand the couplings between the ocean and atmosphere, it is critical to improve our understanding of the processes that control sea spray aerosol (SSA) composition and which ones plays the dominate role in regulating atmospheric chemistry and climate.

The impact of sea spray aerosol (SSA) on climate depends on the size and chemical composition of individual particles that make up the total SSA ensemble. There remains a lack of understanding as to the composition of individual particles within the SSA ensemble and how it changes in response to dynamic ocean biology. Here, we characterize the classes of organic compounds as well as specific molecules within individual SSA particles. The diversity of molecules within the organic fraction was observed to vary between submicrometer- and supermicrometer-sized particles and included contributions from fatty acids, monosaccharides, polysaccharides, and siliceous material. Significant changes in this molecular diversity were observed to coincide with the rise and fall of phytoplankton and heterotrophic bacteria populations within the seawater. Furthermore, the water uptake of individual particles was affected, as learned from studying the hygroscopicity of model systems composed of representative mixtures of salts and organic compounds.