wet heath subarctic ecosystem. The study was directly linked to Pedersens MSc thesis work at CENPERM. The study site is in Northern Sweden and represents a dominant ecosystem type found across the circumpolar region. The study demonstrates the sensitivity and a surprising capacity throughout the entire growing season of a wet heath ecosystem to function as a net CH4 sink. The study further shows that leaf litter addition significantly increases CH4 uptake rates due to a pronounced soil drying. Warming enhances CO2 release, while CH4 uptake is controlled by soil moisture. By integrating both CH4 and CO2 fluxes it was shown, that higher summer temperatures might shift the ecosystem toward a net carbon source due to an increase in CO2 release, thereby enhancing the greenhouse effect. 4. Litter decomposition is a fundamental component of ecosystem carbon and nutrient cycles, with fungi being among the primary decomposers. To assess the impacts of seasonal climatic changes on litter fungal communities and their functioning, Betula glandulosa leaf litter was surface-incubated in two adjacent low Arctic sites with contrasting soil moisture regimes: dry shrub heath and wet sedge tundra at Disko Island, Greenland. Christiansen et al. (2017) investigated the impacts of factorial combinations of enhanced summer warming (using open-top chambers; OTCs) and deepened snow (using snow fences) on surface litter mass loss, chemistry and fungal decomposer communities. Enhanced summer warming significantly restricted litter mass loss by 32% in the dry and 17% in the wet site. Litter moisture content was significantly reduced by summer warming in the dry, but not in the wet site. Likewise, fungal total abundance and diversity were reduced by OTC warming at the dry site, while modest warming effects were observed in the wet site. These results suggest that increased evapotranspiration in the OTC plots lowered litter moisture content to the point where fungal decomposition activities became inhibited. By contrast, snow addition enhanced fungal abundance in both sites but did not significantly affect litter mass loss rates. It was concluded that although buried soil organic matter decomposition is widely expected to increase with future summer warming, surface litter decay and nutrient turnover can be restricted by the evaporative drying associated with warmer air temperatures. In situ ecosys tem methane f luxes measured with closed chamber technique in a wet heath ecosys tem, Abisko, Sweden. Photo: Bo Elber ling CENPERM Annual Report 2017 7 ANNUAL REPORT 2017 CENPERM Center for Permafrost Field sites Brønlundhus Qaanaaq Svalbard Longyearbyen Greenland Zackenberg Disko Qajaa Sweden Kangerlussuaq Nuuk Narsarsuaq Abisko Sermilik Directors welcome The vision of Center for Permafrost Highlights 2017 Højdepunk ter 2017 Deltas are growing as climate is warming Publications & conferences Communication & outreach Educational activities Ongoing research projects & graduate students International collaborators & funding CENPERM sta Photo: Bo Elberling 2 CENPERM Annual Report 2017 Directors welcome The end and the start. The year 2017 has been dominated by the activities reflecting the end of CENPERM I and the start of CENPERM II. As such we have been implementing as much as possible for the revised research plan for 20182022. The plan is now available on our website. The ima The vision of 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 cli Field work at South Georgia . Photo: Bo Elberling. CENPERM Annual Report 2017 5 Highlights 2017 CENPERM highlights of 2017 include intensive fieldwork combined with detailed analyses of remote sensing products. The following four papers published in 2017 highlight the benefits of working multi-disciplinarily and performing both up- and downscaling. Scaling matters. The studies wet heath subarctic ecosystem. The study was directly linked to Pedersens MSc thesis work at CENPERM. The study site is in Northern Sweden and represents a dominant ecosystem type found across the circumpolar region. The study demonstrates the sensitivity and a surprising capacity throughout the ent Højdepunkter 2017 Højdepunkterne for CENPERM i 2017 omfatter flere eksempler på hvor feltarbejde er blevet kombineret med brug og analyse af remote sensing. Følgende fire publikationer offentliggjort i 2017, belyser fordelene ved at arbejde tværfagligt og inkludere både en op- og nedskalering. Studi 4. Nedbrydning af løv er et afgørende element i økosystemets CO2- og næringsstofkredsløb, og her er både bakterier og svampe primære nedbrydere. For at vurdere, hvordan sæsonernes klimaforandringer påvirker svampesamfundene og deres funktion, blev der inkuberet løv af Betula glandulosa på to lavtlig Deltas are growing as climate is warming by Mette Bendixen, postdoc, CENPERM, University of Copenhagen Deltas form where rivers meet the ocean and are shaped by the forces of rivers, waves and tides. Today, most deltas in the world are drowning because of a global rise in sea level. Large parts of In the work published in Nature in October, we show that the coasts of Greenland have an opposite response to a warming climate than the rest of the Arctic. As climate warms, the deltas of Greenland are growing. Key data for this research come from an archive of historical aerial imagery taken by th Publications & conferences Abermann, J., Hansen, B.U., Lund, M., Wacker, S., Karami, M., Cappelen, J. (2017). Hotspots and key periods of Greenland climate change during the past six decades. Ambio 46, 311. Barnhart, K.R., Abbas Khan, S., Box, J.E., Abermann, J., Langley, K., Kroon, A. (2017). Delt transported to anoxic river delta sediments. Microbial Ecology 74, 6-9. Chadburn, S. E., Krinner, G., Porada, P., Bartsch, A., Beer, C., Belelli Marchesini, L., Boike, J., Ekici, A., Elberling, B., Friborg, T., Hugelius, G., Johansson, M., Kuhry, P., Kutzbach, L., Langer, M., Lund, M., Parmentier, F ral variability in surface energy balance across tundra, snow and ice in Greenland. Ambio 46, 8193. Nielsen, C.S., Michelsen, A., Strobel, B.W. Wulff, K., Banyasz, I., Elberling, B. (2017). Correlations between substrate availability, dissolved CH4, and CH4 emissions in an arctic wetland subject to Rousk, K., Pedersen, P.A, Dyrnum K., Michelsen, A. (2017). The interactive effects of temperature and moisture on moss-associated N2 fixation. Theoretical and Experimental Plant Physiology 29, 25-36. Rousk K., Sorensen P.L., Michelsen A. (2017). Nitrogen fixation in the High Arctic: A source of new Priemé A., Blok D., Haugwitz M.S., Vor íšková J., Elberling B. (2017). Arctic soil microbial sensitivity to seasonal dynamics and climate change. In Tate, K. (ed.), Microbial Biomass - A New Paradigm in Terrestrial Biogeochemistry (pp 275307). London, UK: World Scientific Publishing. Poster present Communication & outreach CENPERM continued its series of weekly talks at the Department of Geosciences and Natural Resource Management. These seminars were also held for Phd students and postdocs to present specific parts of their work, to create a forum for sharing of knowledge, problems, and solut Other Bendixen, M. Climate change - facts, uncertainties, and policies, Panel-discussion organized by Uni. of Copenhagen at Folkemødet, Bornholm, Jun. 6. Elberling, B. Plantevækst & Permafrost. Offentligt foredrag i Magisterforeningen, Nov. 23. Fenger-Nielsen, R. Klimaforandringer og Grønlands arkæo May 4. Birger U. Hansen, Thomas Friborg, associate professors, CENPERM/IGN: Presentations on Greenland Ecosystem Monitoring (GEM). May 11. Tao Li, postdoc, CENPERM/BIO: Plant volatiles in a changing environment: stress response, ecological and atmospheric implications. Sep. 21. Bo Elberling, profess Educational activities CENPERMs activities in 2017 include a number of educational efforts. These include both arctic field courses and classic university courses at the basic and advanced levels at the University of Copenhagen. In addition to course taught, a number of M.Sc. theses have been superv Aerial and near-field remote sensing, Dept. of Geosciences and Natural Management, University of Copenhagen, A. Westergaard-Nielsen. Arctic biology, Dept. of Biology, University of Copenhagen, spring, R. Rinnan, A. Michelsen, A. Priemé. Climate change and biogeochemical cycles. Dept. of Biology, Uni Ongoing research projects & graduate students In February, the PhD students held a WriteCamp outside Copenhagen. Like the previous years a special Master theses workshop was held in March with discussion and presentations of projects in progress. A number of the master students participated in the C Faucherre, Samuel: Subsurface carbon and nitrogen pools and potential mobilization in permafrozen soil environments. Supervisors: Bo Elberling and Christian Juncher Jørgensen. Fenger-Nielsen, Rasmus: Predicting and mapping environmental threats to archaeological sites in Greenland under current and Frendrup, Laura Lønstrup: The impact on the nitrogen cycle in an arctic tundra with a changing climate. Supervisor: Per Ambus. Hermesdorf, Lena: Methane oxidation: patterns and drivers. Supervisor: Bo Elberling. Kolstad, Elisabeth Larsen: N cycling at snowbed gradient. Supervisors: Per Ambus, Anders Simonsen, Anne Mette Tholstrup: Environmental impacts of submarine tailings disposal from an iron-ore mine, Norway, completed Jul. 2017. Supervisor: Bo Elberling. Simonsen, Lisbeth: Microbial succession and nitrogen fixation along the chronosequence of a receding glacier in West Greenland, completed International collaborators & funding Research activities at CENPERM continue to be linked to a number of well-established international arctic networks. These cooperation agreements are supplemented by a strong affiliation to internationally recognized researchers. External experts and Center eva British Antarctic Survey, Cambridge (UK): P. Convey, K.K. Newsham and E.M. Biersma. Intl. cooperation at Disko and South Georgia. Shared fieldwork and publications. Delft University of Technology, The Netherland: Computer vision lab. Eidgenössische Technische Hochschule Zürich, Schweiz: T. Crowther. University of Eastern Finland, Department of Environmental Science, Finland: M. Kivimäenpää. Sample treatment, light and scanning electronmicroscopy. University of Edinburgh, School of GeoSciences, UK: I. Myers-Smith, S. Angers-Blondin. Pan-arctic shrub growth meta-analysis. University of Helsinki, Danish Energy Agency (Energistyrelsen): Evaluating monitoring program in Disko Bay. Grant holder: Thomas Friborg. 2016-2017. DKK 450,000. Danish Energy Agency (Energistyrelsen): GeoBasis- Disko. Grant holder: Thomas Friborg. 2017-2018. DKK 1,604,000. Danish Ministry for Research: Integrated Carbon O CENPERM staff Researchers Researchers Albers Christian Nyrop Researcher Ambus Per Professor Andersen Thorbjørn J. Professor Christensen Ditte Marie Trainee Elberling Bo Professor, Director Ernstsen Verner Brandbyge Associate professor Friborg Thomas Associate professor Hansen Birger Ul CENPERM staff Ravn Nynne R. PhD student Schostag Morten Dencker PhD student St Pierre Kyra PhD student, visiting Svendsen Sarah H. PhD student Wang Peiyang PhD student, visiting Technical staff Jacobsen Pia Laboratory technician Madsen Mathias Electronics technician Moser Vagn Laboratory ANNUAL REPORT 2017 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