Microalgal Responses to Changing Sea-Ice Regimes: Insights for Future Antarctic Ecosystems
| Tuesday, August 25, 2026 |
| 4:00 PM - 4:45 PM |
Overview
Dr Rebecca Duncan, Linnaeus University Sweden and University of Technology Sydney
Speaker
Dr Rebecca Duncan
Post Doctoral Resesrcher
Linnaeus University Sweden And University Of Technology Sydney
Microalgal Responses to Changing Sea-Ice Regimes: Insights for Future Antarctic Ecosystems
Abstract Document
Antarctic sea ice is undergoing rapid change, with recent record-low extents highlighting the need to understand how shifts in sea-ice regimes will affect ecosystem structure and function. Sea-ice microalgae are a critical component of polar food webs, yet the mechanisms linking changing ice conditions to community composition and nutritional quality remain poorly understood.
Drawing on extensive Arctic and Antarctic field campaigns spanning sea-ice freeze-up to spring-bloom, land-fast ice, drift ice, and glacier-influenced systems, we investigated community composition, nutritional value, colonisation strategies and physiological health from community to species-specific scales. Across these diverse sea-ice regimes, sea-ice conditions strongly influenced community structure and drove shifts in cellular energy allocation. Higher under-ice light was associated with greater diversity and accumulation of lipids and fatty-acids. Dynamic drift-ice environments supported less diverse communities with lower lipid and fatty-acid content than land-fast ice. Seasonal observations revealed that diatom taxa increased lipid reserves during late-stage ice melt. Complementary mesocosm experiments with natural Antarctic phytoplankton communities revealed species-specific responses to ocean acidification.
Together, these findings provide a mechanistic framework linking sea-ice conditions and environmental change to the energy available to polar food webs. As Antarctic sea ice becomes increasingly fragmented, this extensive Arctic-focused record offers a valuable natural analogue for understanding how changing ice regimes influence ecosystem productivity and biogeochemical cycling, providing insights directly relevant to predicting future Antarctic marine ecosystem responses.
Drawing on extensive Arctic and Antarctic field campaigns spanning sea-ice freeze-up to spring-bloom, land-fast ice, drift ice, and glacier-influenced systems, we investigated community composition, nutritional value, colonisation strategies and physiological health from community to species-specific scales. Across these diverse sea-ice regimes, sea-ice conditions strongly influenced community structure and drove shifts in cellular energy allocation. Higher under-ice light was associated with greater diversity and accumulation of lipids and fatty-acids. Dynamic drift-ice environments supported less diverse communities with lower lipid and fatty-acid content than land-fast ice. Seasonal observations revealed that diatom taxa increased lipid reserves during late-stage ice melt. Complementary mesocosm experiments with natural Antarctic phytoplankton communities revealed species-specific responses to ocean acidification.
Together, these findings provide a mechanistic framework linking sea-ice conditions and environmental change to the energy available to polar food webs. As Antarctic sea ice becomes increasingly fragmented, this extensive Arctic-focused record offers a valuable natural analogue for understanding how changing ice regimes influence ecosystem productivity and biogeochemical cycling, providing insights directly relevant to predicting future Antarctic marine ecosystem responses.
Biography
Dr Rebecca Duncan is a post-doctoral researcher with Linnaeus University, Sweden and University of Technology Sydney (UTS). She received her PhD from UTS and UNIS Svalbard. Her research interest is how projected climate change impacts alter the nutritional value and community composition of polar microalgae, and how these changes influence energy transfer in the polar marine systems. To answer these questions, Rebecca combines extensive fieldwork campaigns with a mix of analytical tools ranging from particle accelerators to classical taxonomy. Rebecca has been working on sea ice ecosystems for the last decade, spending much of her time in the Arctic since 2017. She is also a passionate advocate for women and diversity in polar and field sciences.
