Photochemistry in the marine boundary layer: marine-chromophoric dissolved organic matter and small molecule photosensitizers
The abundance of organic compounds at the surface of oceans - the marine boundary layer - provides a link between ocean biogeochemistry and atmospheric chemistry through physicochemical processes at and near the air−water interface. These processes, in turn, affect primary and secondary aerosol formation and evolution in the atmosphere. The Grassian group is investigating the photochemistry and photosensitizing properties of marine dissolved organic matter (DOM), particularly the chromophoric fraction (m-CDOM). Leveraging the NSF CAICE SeaSCAPE campaign, a large-scale cross-institutional collaborative mesocosm experiment, ongoing studies are currently exploring:
Production and molecular composition of m-CDOM using high-resolution mass spectrometry and UV-VIS analytical approaches.
Partitioning of m-CDOM between bulk seawater, the sea surface microlayer (SSML), and aerosol phases.
m-CDOM reactivity through collaborative investigations of excited state mechanics, photo-oxidation, hydroxyl radical and nitrous acid production, and structure via molecular dynamics/density functional theory calculations.