PICE Talk by Sofia Ribeiro, GEUS

Title: Arctic cryosphere change and marine ecosystems: Holocene perspectives from Greenland

The Arctic cryosphere is a sentinel of climate change. Sea-ice extent and volume have plummeted over the last decades and the Greenland Ice Sheet and arctic glaciers are losing mass at an accelerating rate. Alongside with increasing ice-sheet runoff, the Arctic Ocean is predicted to become seasonally ice-free within decades, a policy-relevant threshold in the Earth System. Yet, the consequences of such changes for arctic marine ecosystems and the people relying on them remain uncertain. Long-term data archived in paleo-records holds valuable lessons for the future.
I will present an overview of our recent and ongoing research activities dedicated to understanding arctic cryosphere changes during the Holocene, and their multifaceted impacts on arctic marine ecosystems. I will present long-term data on the impact of Greenland Ice Sheet runoff on marine productivity, Holocene records of ocean and climate variability around Greenland, and a multidisciplinary assessment of the vulnerability of the globally important sea-ice ecosystem Pikialasorsuaq (the North Water polynya) to climate change. Much of our knowledge on past variability derives from microfossil and biogeochemical proxies that all have limitations such as preservation biases and varying taxonomic resolution or coverage. Sedimentary ancient DNA (sedaDNA) has emerged as a promising tool in understanding Arctic change due to the favorable preservation of DNA at low temperatures, and the possibility to capture a much larger fraction of biodiversity from paleo-archives than what is possible with classical approaches. I will highlight some promising new developments on the use of marine sedaDNA to reconstruct sea ice, and how it holds great potential for expanding our understanding of past changes in the Polar regions.