Highlights 2020 Highlights 2020 is dedicated to the PhDstudents of CENPERM. The students, despite Covid-19 and continued difficulties, have kept their motivation levels high and been able to continue their research, working intensively on specific projects, and for some defended online. Three multidisciplinary publications linked to PhD-projects are highlighted below: all integrate aspects from bioscience and geoscience, and show that we still can be surprised by the complex responses of the Arctic to climate change, with or without humans being present. 1. Soil water chemistry is an important component in soils for understanding climate feedbacks, plant growth, microbial turnover and net greenhouse gas emissions. In Soil Biology and Biochemistry Rasmussen et al. (2020) we assess the soil water chemistry in a low arctic Greenlandic mesic tundra heath and a fen. The sites have been subjected to factorial treatments of summer warming using open top chambers, snow addition using snow fences (which increase soil temperature in late winter), and shrub removal mimicking herbivory attack. Measurements were made over contrasting growing seasons (20132016). Ambient nutrient concentrations in the mesic tundra heath decreased throughout the growing season and increased during leaf senescence in the autumn. In contrast, nutrient concentrations were highest during peak growing season in the fen. Summer warming in the heath did not change the availability of nutrients, however changes in nutrients such as nitrate were observed in combination with shrub removal or snow addition treatments, highlighting the complexity of ecosystem responses to single and multiple climate effects. The study shows how soil water chemistry is vegetation-specific, and that treatment effects 6 CENPERM Annual Report 2020 on nutrient cycling are surprisingly limited when comparing multiple years with contrasting precipitation patterns. The combination of multiyear and multi-site studies is therefore important for understanding future biogeochemical dynamics in Arctic landscapes. 2. In Global Change Biology Pedersen et al. (2020) we demonstrate a new and important climate feedback mechanism that may act to counterbalance CO2 release from organic matter degradation. We show that warming in the Arctic can increase plant-available nutrients from both accelerated top-soil decomposition, as well as deep-soil permafrost thaw. Plants take advantage of nitrogen (N) made available by soil decomposition and permafrost thaw, and incorporate it into new above-ground biomass. Plant species-specific N uptake was measured immediately after N-release (autumn) and after one year. We found that high arctic plants actively foraged for N after the peak growing season. While some plant species (Carex rupestris, Dryas octopetala, Kobresia myosuroides) preferred top-soil N, the shrub Salix arctica acquired N from deeper soil layers. All plants were able to obtain N from the permafrost thaw front from approximately 1 m depth, both in autumn and during the following growing season. This demonstrates the importance of permafrost-released N as a new nutrient source for arctic plants. It can be concluded that thawing permafrost can release CO2 from stored organic matter, but also kick start a positive feedback by making nutrients available for some plants to grow better and consequently counterbalance carbon loss from degrading permafrost via above-ground plant growth. 3. Climate change threatens both natural as well as many well-preserved archaeological sites In Archaeometry Fenger-Nielsen et al. (2020) ), we ANNUAL REPORT 2020 CENPERM Center for Permafrost Field sites Brønlundhus Qaanaaq Svalbard Longyearbyen Greenland Zackenberg Disko Qajaa Sweden Kangerlussuaq Nuuk Narsarsuaq Abisko Sermilik Directors welcome Visions and aims Highlights 2020 Højdepunk ter 2020 Arctic wildf ires a burning hot topic Publications & conferences Communication & outreach Educational activities Ongoing research projects & graduate students International collaborators & funding CENPERM staff 3 4 6 8 10 12 16 2 CENPERM Annual Report 2020 Directors welcome The year 2020 has been a special year in many ways; a year with changes for almost everyone and difficult in different ways for most due to Covid-19. We have been able to complete most of the planned field work by continuously making changes according to regulations. Unfortunately, Visions and aims Center for Permafrost Microbial activity Plant ecology CENPERM Permafrost soil & landscape dynamics CENPERM integrates multidisciplinary research of biogeochemical and physical processes in a climate-vegetation-soil-microorganismpermafrost approach in transects across the major c CENPERM Annual Report 2020 5 Highlights 2020 Highlights 2020 is dedicated to the PhDstudents of CENPERM. The students, despite Covid-19 and continued difficulties, have kept their motivation levels high and been able to continue their research, working intensively on specific projects, and for some defended online. Three multid present the first Arctic multi-threat assessment focusing on the Nuuk region of Greenland. In this region, more than 300 archaeological sites are already threatened by exposure to impacts from microbial degradation, permafrost thaw, vegetation growth and erosion driven by climate change. Within the Højdepunkter 2020 Højdepunkter 2020 er dedikeret til vores ph.d.-studerende ved CENPERM. På trods udfordringerne som følge af Covid-19 restriktionerne, har de ph.d.-studerende bevaret motivationen på et højt niveau, fortsat deres forskning, afsluttet diverse delprojekter, og nogle har måtte forsvare 3. Klimaforandringer truer de velbevarede arkæologiske områder i Arktis. I Archaeometry præsenterer Fenger-Nielsen et al. (2020) det første forsøg på i en arktisk sammenhæng, at sammenholde de mange trusler i en samlet trusselvurdering med fokus på Nuuk-regionen i Grønland. I denne region er der mer Arctic wildfires a burning hot topic by Lena Hermesdorf, PhD Student, CENPER M, University of Copenhagen In recent years, wildfires in arctic tundra landscapes have increased in frequency, and models project them to increase in the future due to warmer and drier summers. To date, little is known a In order to analyse whether the fire and destruction of vegetation led to changes in soil processes, and hence in GHG fluxes, we measured the exchange rates of all three GHGs and took several soil samples during three growing seasons (2017-2019). In this way we can differentiate between effects that Publications & conferences International journals Andersen, E. A. S., Michelsen, A., Fenger-Nielsen, R., Hollesen, J., Ambus, P. L., Elberling, B. (2020). Nitrogen isotopes reveal high N retention in plants and soil of old Norse and Inuit deposits along a wet-dry arctic fjord transect in Greenland. birch forest via effects on soil thermal regime and sequestration of deposited nitrogen. Journal of Ecology 13567. Kristensen, J. A., Michelsen, A., Metcalfe, D. B. (2020). Background insect herbivory increases with local elevation but makes minor contribution to element cycling along natural gradie Rasmussen, L. H., Michelsen, A., LadegaardPedersen, P., Nielsen, C. S., Elberling, B. (2020). Arctic soil water chemistry in dry and wet tundra subject to snow addition, summer warming and herbivory simulation. Soil Biology and Biochemistry 141, 107676. Ravn, N. R., Elberling, B., Michelsen, A. (202 Westergaard-Nielsen, A., Balstrøm, T., Treier, U., Normand, S., Elberling, B. (2020). Estimating meltwater retention and associated nitrate redistribution during snowmelt in an Arctic tundra landscape. Environmental Research Letters 15, 034025. Wester-Larsen, L., Kramshøj, M., Albers, C. N., Rinnan, Communication & outreach CENPERM continued its series of regular talks in spite of the Covid-19 situation; however, most talks during the year have been via zoom. By meeting regularly, it was possible to keep in touch and share problems and solutions within the Center. Unfortunately, a planned write Elberling, B.: Four Citizen Science talks onboard Antarctic Cruise: Climate and environmental changes: trends and variations, Penguin colonies: a hotspot for greenhouse gas emissions, Dry Valleys: the cold desert but surprisingly alive, The Antarctic continent in a global context. Jan. Talks Elber Jun. 11. Emily Pickering Pedersen. PhD student, CENPERN, BIO. Foraging deeply: Depth-specific plant nitrogen uptake in a high arctic permafrost ecosystem. Sep. 3. Welcome back from the field. Short reports on fieldwork. Sep. 17. Jesper Riis Christiansen, IGN/ Christian Juncher Jørgensen, AU. Methane Educational activities CENPERMs activities in 2020 include a number of educational efforts, which this year mainly classic university courses at the basic and advanced levels at the University of Copenhagen. In addition to course taught, a number of M.Sc. meant theses have been supervised (see: Ongo Climate change and biogeochemical cycles. Dept. of Biology, University of Copenhagen, autumn, R. Rinnan, K. Rousk, P. Ambus, G. Schurgers. Climate change - an interdisciplinary challenge. Dept. of Geosciences and Natural Resource Management, University of Copenhagen, autumn, R. Rinnan, G. Schurgers, Ongoing research projects & graduate students Postdoc and Assistant Professor projects Alvarenga, Danillo: Interactions between cyanobacteria and moss-hosts. DImperio, Ludovica. Postdoc: Soil-plant interactions and greenhouse gas dynamics in permafrost-affected ecosystems. Kramshøj, Magnus. Postdoc Defended PhD thesis 2020 Fenger-Nielsen, Rasmus: Archaeological sites threatened by climate change: a regional perspective from Greenland. Supervisors: Bo Elberling, Jørgen Hollesen and Aart Kroon. Defended: May 2020. Ongoing PhD projects 2020 Baggesen, Nanna: Emissions of biogenic volatile organ Xu, Wenyi: Fire in Arctic tundra - impacts on bio-geochemical cycles. Supervisor: Per Ambus. Yun, Hanbo: Quantifying and modelling methane dynamics in contrasting landscapes of the Qinghai-Tibetan Plateau. Supervisor: Bo Elberling, co-supervisor: Ludovica D Imperio and Wenxin Zhang. Zastruzny, Sebas Ongoing M.Sc. projects: 7 Christensen, Maj Paornak Sofie: The effects of enhanced precipitation and phosphorus addition on carbon dioxide and methane fluxes in heath tundra in Greenland. Supervisor: Anders Michelsen. Jacobsen, Cathrine Kallestrup: Plant ecophysiology, carbon cycling and vegetation International collaborators & funding Research activities at CENPERM are linked to a number of well-established international arctic networks. These cooperation agreements are supplemented by a strong affiliation to internationally recognized researchers. CENPERM has continuously extended the intern Los Alamos National Laboratory, USA: C. Andresen, permafrost impacts on hydrology. Michigan State University, USA: Tiedje J.; microbial studies, scientific publications. The Netherlands Central Organisation for Radioactive Waste (COVRA). NOAA (National Oceanic and Atmospheric Administration) Global University of Bergen, Norway: L. Øverås. University of Boulder, Institute for Arctic and Alpine Research (INSTAAR), Colorado, USA: I. Overeem, K. Barnhart. Coastal changes in Greenland. University of Eastern Finland, Department of Environmental Science, Finland: M. Kivimäenpää. Sample treatment, lig Danish Ministry for Research: Integrated Carbon Observation System, Research Infrastructure (ICOS-RI). Grant holder: Thomas Friborg (2016-2021): 6.5 mio. Independent Research Fund Denmark, Sapere Aude DFF-Research leader: Climatic, ecological and molecular controls of nitrogen fixation in pristine s CENPERM staff Researchers Ambus Per Lennart Professor Andersen Thorbjørn J. Professor Christiansen Casper Tai Postdoc Elberling Bo Professor, Director Friborg Thomas Associate professor Hansen Birger Ulf Associate professor Hollesen Jørgen Senior Researcher Kroon Aart Associat CENPERM staff PhD students Baggesen Nana PhD student Danielsen Birgitte Kortegaard PhD student Fenger-Nielsen Rasmus PhD student Hermesdorf Lena PhD student Hornum Mikkel Toft PhD student Kylborg Sarah Estela PhD student Liu Yijing PhD student Pedersen Emily Pickering PhD student P ANNUAL REPORT 2020 The Danish National Research Foundation (DNRF) is an independent organization established by the Danish Parliament in 1991 with the objective to promote and stimulate basic research at the highest international level at the frontiers of all scientific fields. The Center of Excell