Sea spray aerosols are microscopic droplets of seawater that are formed by bubble bursting at the ocean surface. They play a major role in cloud formation, climate, and are suspected to affect human health after inhalation. Until now, research at VLIZ and Ghent University has focused on the presence and human health effects of biogenic chemicals inside sea spray aerosols. We found that the enrichment of marine biogenic chemicals inside sea spray aerosols shows strong intervariability, which we believe is caused by differences in foam stability. With this PhD, we want to get a better understanding of sea foam formation, composition, stability, and its role in the aerosolization of waterborne chemicals and bacteria. In particular, we want to investigate whether the production of transparent exopolymer particles (mainly polysaccharides) by bacteria and phytoplankton (released naturally or via viral lysis of these hosts), or other macromolecules present in the sea surface microlayer such as proteins or lipids can be used to predict the abundance and lifetime of sea spray aerosols and the enrichment of biogenics within them. The research integrates field work – mainly beach sampling – with experimental approaches in the lab, combining biological observations (flow cytometry; plankton imaging) with analytical chemistry and use of technical devices applied to aerosols such as the MART (used to approach natural aerosol formation), ocean water wave basin (used to approach natural physical and chemical conditions of the sea), or automatic aerosol samplers.
The overall aim of this PhD will thus be to have a better understanding of the formation, stability and compositions of both the sea foam and the sea spray aerosols which we expect to be linked