Biogeochemical aerosol processes in Southern Greenlandic fjord systems

Greenlandic fjord ecosystems undergo accelerated change as they are at the nexus of the pressures from the ocean, ice, land and atmosphere. The Swiss Polar Institute Flagship program GreenFjord (Greenlandic fjord ecosystems in a changing climate: socio-cultural and environmental interactions) investigated biogeochemical aerosol processes in two contrasting fjords in southern Greenland between 2022 and 2025. One fjord represented a system, where glaciers still terminate in the ocean (marine-terminating fjord), while another represented a system, where only streams from land-terminating glaciers (land-terming fjord) enter the ocean. The two ways of adding fresh-water result in very different fjord dynamics of water and nutrient movement, and therefore in different microbial productivity. In addition, the land surface types surrounding the fjords are also distinct.From an ocean perspective and to understand if these differences impact atmospheric chemical composition, we performed measurements of new particle formation, volatile organic compounds and aerosol chemical composition, and find indeed different processes across the fjords with impacts on the cloud condensation nuclei (CCN) budget. From a land perspective, in a land-terminating system, glacial outwash plains typically form and constitute potentially large sources of ice nucleating particles (INP). We investigated the freezing spectra and atmospheric contribution of glacial dust to the aerosol population.This presentation will provide an overview of the GreenFjord project and delves into the natural contribution of CCN and INP from fjord systems.