Publication abstract: The oceans cover nearly three-quarters of Earth’s surface and produce vast quantities of sea spray aerosols (SSA) which are commonly assumed to contain mostly inorganic salts. However, recent studies have shown that SSA particles also contain biological species including proteins, lipids, viruses, and bacteria. In this study, we show for the first time that diverse microbial en-zymes (protease, lipases, and alkaline phosphatase) are ejected into the atmosphere and remain active, leading to the dynamic evolution of the composition of SSA in both controlled laboratory and coastal field studies. Compared to bulk seawater, the measured rates in SSA particles were 1-2 orders of magnitude higher suggesting that these catalytic biotic reactions are enhanced at interfaces. Simulations reveal that enzyme-containing SSA particles can rapidly coagulate with pre-existing aerosols, thus transferring enzymes to a wider range of marine aerosols. These new-ly revealed reaction pathways will efficiently and profoundly change SSA composition, surface properties, and the ability to form clouds and therefore need to be taken into account in future atmospheric and climate models.