Abstract: My research explores how marine microorganisms influence the production and variability of sea spray aerosols (SSA) — ocean-derived particles that affect clouds, radiation, and climate. High-resolution measurements across the Atlantic and Pacific Ocean basins and controlled algal bloom experiments revealed consistent day–night cycles in aerosol emissions, with higher concentrations during daylight hours. These patterns suggest that biological activity, potentially linked to photosynthetic processes, enhances bubble formation and SSA release. We also observed clear diurnal changes in the airborne microbiome above a coral reef, with distinct daytime and nighttime community compositions, further supporting a biological control on aerosol dynamics. In addition, we found a progressive decrease in SSA concentration throughout algal bloom succession, suggesting that the buildup of biological surfactants suppresses SSA production and reflects a dynamic connection between microbial physiology and SSA emission. Finally, we collected airborne marine bacteria above an algal bloom, which remained active and were able to infect and kill marine algae in the lab, forming a biological bridge between the ocean and the atmosphere. Together, these findings highlight how microbial processes may play a significant yet underappreciated role in regulating ocean–atmosphere interactions and, ultimately, Earth’s climate.