The observed decline of Arctic sea ice during the past decades is one of the most striking consequences of global change. Sea ice is an important component of global climate, and its dynamics have a large impact on the primary productivity of Arctic marine ecosystems, with repercussions to the entire food web, carbon cycling (including CO2 uptake by the ocean), and human activities (e.g. fisheries and navigation). However, our understanding of Arctic sea ice variability is severely limited by the fact that reliable datasets are only available for the past ca. 30 years satellite data).
The main goal of the project is to reconstruct past sea ice variability and its impact on primary productivity, with implications for the biogeochemical cycle and ecosystem functioning. This will be achieved by analyzing marine sediment records retrieved from fjord and shelf areas in Northeast Greenland using a novel network of biogeochemical proxies. The proxy records will be calibrated and refined by studying surface sediment samples, modern sea ice and plankton assemblages, and by DNA analyses of indicator species. The new data will be incorporated into sea ice and ecosystem models to better predict future scenarios for the Arctic (data assimilation modeling).
The project focuses on Northeast Greenland, a key area from which climate and sea ice studies are still virtually absent. This area is the main gateway for sea ice export from the Arctic Ocean, and Atlantic-Arctic water mass exchange. Furthermore, the NE Greenland coast is characterized by fjords and polynyas (hotspots of productivity), and the fjord sedimentation rates are suitable for obtaining high-resolution records.
Study areas include:
- Station Nord/ Danmarksfjord
- Young Sound
- Greenland Sea/ Fram Strait
Marine sediment records are valuable archives of past climate and environmental variability. Key parameters such as temperature, salinity, sea ice, and productivity can be reconstructed using a combination of geochemical, sedimentological and micropaleontological proxies. The main phytoplankton groups (diatoms and dinoflagellates) have a rich sediment record, from which changes in diversity and community structure can be inferred. Sediment cores also contain living cells of marine primary producers and their DNA.
Lipid biomarkers have emerged over the past years as particularly promising for the reconstruction of sea ice. IP25 is produced by certain diatoms in the sea ice and accumulates in sediments over time, leaving a long-term imprint of past sea ice.
Main project partners and collaborators
- GEUS: Niels Nørgaard-Pedersen, Kaarina Weckström, Antoon Kuijpers, Naja Mikkelsen.
- Copenhagen University: Marianne Ellegaard, Thorbjørn J. Andersen.
- Aarhus University/ARC: Marit Solveig-Seidenkrantz, Søren Rysgaard.
- Tromsø University: Matthias Forwick, Tine Rasmussen.
- Laval University, Quebec: Guillaume Massé