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 forsvaret deres afhandlinger online. Tre tværfaglige videnskabelige artikler, der hver er tilknyttet et ph.d.-projekter, fremhæves her. Artiklerne integrerer aspekter fra både bio- og geovidenskab og viser, at vi fortsat bliver overrasket over hvor komplekst Arktis reagerer på nutidige klimaforandringer både i forsøg og under naturlige forhold. 1. Jordvandskemi er en vigtig del af jordmiljøet for at forstå klima-feedbackmekanismer koblet til plantevækst, mikrobiel omsætning og nettoemissionen af drivhusgas. I en artikel i Soil Biology and Biochemistry undersøgte Rasmussen et al. (2020) jordvandskemien i en lavarktisk tundrahede og et kærområde i Grønland. Forsøgsområderne har været manipuleret på 3 måder og dertilhørende kombinationer: sommeropvarmning i form af åbne klimakamre, ekstra sne i form af snehegn, (der øger jordtemperaturen i slutningen af vinteren), og fjernelse af småbuske (for at simulerer angreb fra planteædere). Der blev foretaget målinger i perioden 20132016, hvor der var stor variation i vejret fra år til år. Koncentrationen af næringsstoffer på tundraheden faldt i løbet af hver vækstsæsonen og steg igen om efteråret samtidig med løvfald. I kærområdet var der modsat højest indhold af næringsstoffer i vækstsæsonen. Sommeropvarmning på heden ændrede ikke tilgængeligheden af næringsstoffer, dog forekom der ændringer i visse næringsstoffer - såsom nitrat - i forbindelse med fjernelse af buske eller ved ekstra sne. Dette understreger kompleksiteten i økosystemers reaktion på en eller flere klimapåvirkninger. Undersøgelsen viser 8 CENPERM Annual Report 2020 også, hvordan jordvandskemien varierer mellem forskellige vegetationstyper, og at den fysiske indvirkning på næringskredsløb er overraskende begrænset, når man sammenligner flere år med forskellige snemængder. Det er derfor vigtigt, fortsat at kombinere undersøgelser for flere år og fra flere vegetationstyper for at forstå og forudsige, hvordan et arktisk landskab vil reagere på fremtidige klimændringer. 2. Hvor permafrost tør kan der frigives både CO2 og plantenæringsstoffer ved nedbrydning af organisk stof. Det er et åbent spørgsmål, om planter kan udnytte denne ekstra næringsstoffer og derved vokse og optage mere CO2 fra atmosfæren. Pedersen et al. (2020) viser i en artikel i Global Change Biology, at planter kan optage kvælstof (N), som er frigivet under rodzonen knyttet til en øget nedbrydning samt kvælstof frigivet ved optøning ved grænsen til permafrosten. Planteoptagelse af kvælstof blev målt umiddelbart efter N-frigivelse (efterår) og efter et år. Resultaterne viser, at arktiske planter aktivt udnytter denne ekstra pulje af kvælstof også sent i vækstsæsonen. Alle undersøgte plantearter kunne optage N fra tøet permafrost ned til cirka 1 meters dybde. Nogle plantearter (Carex rupestris, Dryas octopetala, Kobresia myosuroides) var bedre til at udnytte den mere overfladenære pulje af kvælstof, mens fx busken Salix arctica var bedre til at udnytte kvælstof frigivet fra dybere jordlag. Dette viser vigtigheden af permafrost-frigivet N som en ny næringsstofkilde for arktiske planter. Vi konkluderer, at optøende permafrost kan frigive CO2 fra opbevaret organisk stof, men også kickstarte en positiv feedback-mekanisme ved at gøre næringsstoffer tilgængelige for nogle planter, så de har bedre vækstbetingelser og efterfølgende kan reducere økosystemets kulstofstab knyttet til permafrost, der tør ved en øget plantevækst over jorden. 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