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

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.