Thirty years of arctic primary marine organic aerosols: patterns, seasonal dynamics, and trends (1990–2019)

Abstract

Changing Arctic climate conditions have accelerated sea ice retreat, altering ocean–atmosphere interactions and marine ecosystems. Reduced sea ice cover likely enhances emissions of primary marine organic aerosol (PMOA) through bubble bursting, with implications for aerosol–cloud interactions. This study examines the emission patterns, seasonality, and historical trends of key PMOA species (dissolved carboxylic acidic containing polysaccharides, PCHO; dissolved combined amino acids, DCAA; polar lipids, PL) within the Arctic from 1990 to 2019. Surface ocean concentrations of marine biomolecules, derived from a biogeochemistry model used in the ECHAM-HAM aerosol–climate model, exhibit pronounced seasonal cycles. PMOA emissions show strong variability, driven by marine productivity and sea-salt emissions, with maxima from May to September. Total PMOA emissions increased by about 12 %, and the burden rose by 4 % between 1990–2004 and 2005–2019. A 30 year summer trend (July–September) indicates a rapid decline in sea ice, accompanied by increasing concentrations of organic groups in inner-Arctic waters. Positive PMOA emission anomalies have become more frequent over the past 15 years, and total PMOA production has increased by 0.8 %yr-1 since 1990. Differences among biomolecular types persist, with PCHO showing the strongest increases in both emissions (1.3 %yr-1) and aerosol concentrations (0.8 %yr-1).