VOC Emissions From a Mesocosm Bloom Experiment: Untangling Abiotic and Biotic Processes

Duyen Dang1, Michael Rui Clemente Alves1, David Gonzales1, Sarah Amiri2, Kimberly A Prather3 and Vicki H Grassian4, (1)University of California San Diego, Chemistry and Biochemistry, La Jolla, CA, United States, (2)University of California Santa Barbara, Santa Barbara, CA, United States, (3)Scripps Institution of Oceanography, La Jolla, United States, (4)University of California San Diego, Chemistry and Biochemistry, La Jolla, United States
Sea spray aerosols (SSA) have been shown to have a major impact on our climate, yet its composition and climate relevant properties are still poorly understood. Specifically, primary aerosols are generated mechanically through the breaking of waves via bubble bursting, suspending particles into the air above the ocean surface. Secondary marine aerosols (SMA) are formed through the nucleation of semi-volatile organic compounds. Many marine VOCs are directly emitted through by marine biology such as phytoplankton, bacteria, and viruses, usually due to environmental stresses, quorum sensing, defense mechanisms, light-initiated metabolisms, and more. Abiotic VOCs are formed via interfacial photochemistry at the sea surface microlayer (SSML). These photochemically produced VOCs have been recently highlighted as a large potential source of gas phase species in our atmosphere – potentially driving processes important to the Earth’s climate. In this mesocosm study, bulk seawater from a controlled phytoplankton bloom was collected, where its headspace was analyzed using an Orbitrap mass spectrometer with a modified atmospheric pressure chemical ionization probe. The results present temporal compositional changes of the gaseous emissions from the sea water throughout a bloom cycle.