Evolutionary history of Arctic species and geological history of the High Arctic Love Dalén – Stockholm University This application concerns the land research activities of the North Green Earth Ocean Ecosystem Observatory (GEOEO) expedition endorsed by the Swedish Polar Research Secretariat (SPRS). The main goal is to study prehistoric changes in Greenland, but depending on sea-ice conditions, some activities might be needed in Canada. The Arctic has a complex history of species colonization and extinction. We hope to uncover more of this history, such as the arrival and disappearance of muskox, and how climate changes affected marine ecosystems. One aspect of the project will use a palaeogenomic approach, where DNA from ancient materials is analyzed to explore ecosystem changes in marine and terrestrial environments. We will mainly focus on DNA from sediments, especially from lake bottoms, as well as ancient and recent plant and animals remains (bones and teeth). The objective is to investigate the biogeography and evolutionary history of the muskox and other wild animals. This will enable us to assess the genetic variation and structure in comparison with populations from other parts of Greenland as well as northern Canada, such as earlier work on muskox we have been involved in (Pečnerová et al. 2024, Molecular Ecology). This type of study provides insights on how an animal population can survive population threats such as small population sizes and low genetic diversity. Such knowledge can help improve predictions of how ecosystems might change in the future and allow for proactive management strategies. Sampling lake sediment cores will be done using a custom-built raft and Nesje coring system. Initial DNA analyses will be done onboard Oden, with more in depth DNA sequencing done after the end of the expedition at the Centre for Palaeogenetics in Stockholm. Initial DNA analyses will be done onboard Oden, with more in depth DNA sequencing done after the end of the expedition at the Centre for Palaeogenetics in Stockholm. Another objective of our study is to create a database of high-resolution sensitive proxies using driftwood and shrub samples, and to use this data to provide a novel field reconstruction of temperature for the northernmost land latitudes. We plan to use driftwood samples, as well as deciduous and evergreen Arctic tundra dwarf shrub species samples to evaluate annual growth. This will allow us to determine plants growth rate as well as the impact of anomalously high summer temperatures on growth. By doing this, we aim to provide new and accurate data on how temperatures have fluctuated over many years in the Arctic, helping us better understand climate patterns and their impacts on these sensitive regions. In a context of climate change, such information is essential to implement effective management strategies. Another part of the project focuses on long-term geological history. The region has a unique and undisturbed Proterozoic-Paleozoic section of the so-called passive margin of the palaeocontinent Laurentia (proto-northern America), which we aim to study to understand how continental margins form. We will collect sedimentary and metamorphic rocks from this northern region, sampling loose rocks to minimize landscape disturbance. We will use various analytical techniques, including light microscopy and mass spectrometry, to analyze these rocks and create a crust-mantle model of the region. Sampling locations will depend on the icebreaker Oden’s route and weather conditions. All activities will be carried on the northern tip of Ellesmere Island, using the icebreaker Oden as our base, with short helicopter trips to the terrestrial sites. Various trips (up to 15) could be taken between August 1, 2024, and September 30, 2024, depending on sea-ice conditions and Oden’s route, and will involve up to 10 of the researchers onboard Oden. There will be no overnight stays and no camp will be established. The nearest community of Grise Fjord is approximately 500km from the suggested field sites; therefore, no community should be affected by our activities. We will avoid sensitive areas such as the Quttinirpaaq National Park and designated polar bear denning areas. However, we anticipate that there will naturally be a broad general interest for the expedition, and we should provide entertaining and factual information, when possible, made available online to the general public. We feel that the best format for this is a blog, where we can provide sufficient information in short (three or four paragraphs)but frequent posts that we upload at least several times per week. The blog will cover specific occurrences and conditions that will be of interest and relevance to Nunavut communities. Other types of social media such as X (previously Twitter) and Facebook will also be used. Results and progress will also be shared with all regulatory agencies in Nunavut.