09:45–10:00 | ABSTRACT 1231
EAST ANTARCTIC POLYNYAS ARE GROWING AND GREENING
Coastal Antarctic polynyas are critical physical and biological hotspots, driving dense shelf water formation, sustaining early-season phytoplankton blooms, and supporting highly productive marine ecosystems. Yet, their seasonal and interannual variability remains poorly constrained because of sparse observations. Here, we present a 23-year assessment (2003–2025) of nine major East Antarctic coastal polynyas. We combine satellite observations of chlorophyll-a from the Ocean Colour Climate Change Initiative (OC-CCI), sea-ice concentration from AMSR-E/2, wind speed from the Cross-Calibrated Multi-Platform (CCMP) product, and photosynthetically available radiation from GlobColour. These datasets are used to quantify long-term trends in biological production and to investigate the roles of wind, light, and sea-ice variability in driving these trends. Chlorophyll concentrations increased significantly across all nine polynyas over the study period. These biological changes coincide with substantial shifts in polynya physical characteristics: all polynyas decreased in extent before 2016 but have expanded since, consistent with the recent Antarctic sea-ice regime transition. The strong correspondence between changing polynya area, sea-ice conditions, and chlorophyll-a highlights the sensitivity of coastal Antarctic productivity to large-scale climate variability. By integrating multiple long-term satellite records, this work provides new insight into the mechanisms regulating Antarctic biological production and advances our ability to predict the future response of Southern Ocean ecosystems to climate change.
Leo Rolland*, University of Tasmania, [email protected]
Sophie Bestley, University of Tasmania, [email protected]
Christina Schallenberg, Commonwealth Scientific and Industrial Research Organisation, [email protected]
Jakob Weis, University of Tasmania, [email protected]
