Ocean-derived atmospheric aerosols can affect radiative forcing via acting as cloud condensation nuclei and ice nuclei as well as affecting biogeochemical cycle of bioelements. Marine atmospheric aerosols largely consist of organic matter (OM) associated with phytoplankton and dissolved organic matter in seawater. In recent years, much effort has been devoted to examining linkages between the chemistry of sea spray aerosols (SSAs) and the biological and chemical conditions of surface seawater (SSW). However, recent field studies have suggested that there are missing chemical and biological processes affecting marine aerosol production in current emission parameterizations, such as chemical/biochemical forms of OM associated with microbial activity in SSW.

We have investigated the chemical transformation organic carbon and organic nitrogen during the SSW-to-SSA transfer of OM based on the cruise measurements in the Pacific Ocean. Direct comparison of chemical characteristics between SSA and SSW measured by fluorescence spectroscopy in combination with stable carbon isotope analysis, demonstrated that the ratios of humic-like and protein-like substances in the SSAs were significantly larger than those in the bulk SSW. The results suggest significant decomposition of protein-like dissolved organic carbon (DOC) on a timescale of a half to one day and/or preferential production of humic-like substances in the atmospheric aerosols regardless of the particle size. Furthermore, comparison between organic aerosol mass and particulate organic carbon (POC) in SSW linked to the development/aging of diatom bloom indicates that the mass fraction of OM in submicrometer SSA is likely linked with aging of diatom bloom.

These studies provided unique insights into the complex transfer of biologically-derived OM from the ocean surface to the atmosphere. Brief overview of the research activities will be presented on the cruise measurements in the North Pacific with some major findings on biogeochemical linkage in the ocean-atmosphere interface via particulate OM.