Ocean Composition Controls Abiotic Emission of Volatile Organic Compounds

Indirect, abiotic mechanisms near the air/water interface (e.g., photochemistry and multiphase oxidation) lead to the emission of (Volatile Organic Compounds) VOCs into the atmosphere. In a lab study, the VOC emission from abiotic mechanisms is evaluated as a function of seawater composition. Photochemical and oxidation mechanisms lead to comparable VOC emission fluxes which scale closely with the total and dissolved organic carbon content of the seawater. However, the composition of the seawater sample can strongly affect the emission fluxes of specific molecules. For example, nonanal fluxes from oxidation correlate closely with the phytoplankton abundance in the samples, indicating that unsaturated lipids may be the substrate. Conversely, the best predictor for the nitrogenated VOC flux under irradiation conditions is photosynthetic prokaryotes (i.e., cyanobacteria) abundance.

Reference: Schneider, S.R., Collins, D.B., Boyer, M., et al. (2024) Abiotic Emission of Volatile Organic Compounds from the Ocean Surface: Relationship to Seawater Composition. ACS Earth Space Chem., 8 (9), 1913-1923. https://doi.org/10.1021/acsearthspacechem.4c00163