Impacts of wildfire aerosol on carbon uptake and sea-ice in the East Siberian Sea

The frequency of wildfires has increased in the Siberian region. Wildfire plumes carrying black carbon and biologically important elements may have impacts on downwind ocean regions including Arctic seas such as the East Siberian Sea (ESS). However, the responses of marine environments to the wildfire plume introduced to the ESS are not well known. In this study, we tried to identify changes in ocean phytoplankton and sea-ice associated with wildfire activities by utilizing satellite-based and reanalysis data. The amount of carbon produced by wildfires in Boreal Asia coincides with the concentration of black carbon, indicating that wildfires are responsible for the majority of the black carbon in the atmosphere. In addition, we could detect wildfire plume-derived significant increases in ocean carbon uptake from satellite-based bio-optical variables (phytoplankton growth and biomass concentration). Summertime black carbon deposition has more than doubled over the last decade, and black carbon deposition was highly correlated with sea-ice melting rate, implying a contribution of black carbon deposition on sea-ice melting, which may increase ocean productivity by enhancing light availability in the upper ESS.