Grønlands Naturinstitut

Abstract Once nearly eradicated from Europe, grey wolves ( Canis lupus ) have recently undergone a remarkable demographic recovery, but their long-term survival remains precarious. By analyzing 1,001 genomes, we uncover a mosaic of distinct evolutionary lineages, not a single recovering population. Northern populations exhibit Asian wolf ancestry, while southern populations preserve ancient Holocene lineages, with dog introgression varying by region. Isolated wolves from the Scandinavian, Italian, and Iberian peninsulas harbored particularly high levels of inbreeding and fixed deleterious mutations. Signatures of genome erosion were widespread across Europe, with many populations falling well short of the minimum size recommended for long-term survival. Our study reveals the complex tapestry of wolf ancestry and variation across Europe, which calls for nuanced, regional conservation plans founded in genetic monitoring.

Abstract Peatlands store about one‐third of total global soil carbon. Vegetation composition strongly regulates peatland carbon dynamics. Global warming and climate‐driven ecohydrological changes are expected to alter peatland vegetation composition, necessitating accurate simulation of vegetation dynamics to predict future fate of peatland carbon. We incorporated six plant functional types (PFTs) into the ORCHIDEE‐PEAT model to represent bryophytes (mosses), C3 graminoids (sedges and grasses), boreal broadleaf deciduous shrubs, boreal needleleaf evergreen trees, tropical evergreen and raingreen (water‐driven deciduous) trees growing in peatlands. The introduction and elimination of each PFT in response to bioclimatic conditions, as well as sapling establishment, growth, mortality, and competition among PFTs, are explicitly modeled. Simulated vegetation distributions align well with site‐level observations from West Siberian wetlands, where extensive vegetation composition measurements are available for model evaluation. The model slightly overestimated gross primary productivity (GPP) across 60 sites. Evaluation using global satellite‐derived land cover, leaf area index and GPP data was encouraging, though challenges lie in the lack of observational data specific to peatlands. From 1901 to 2020, simulated tropical peatland vegetation composition remains relatively stable. In northern peatlands, as a result of warming and declining water table, bryophyte and C3 graminoid cover decrease by 0.2 (13%) and 0.1 (13%) million km 2 , respectively, while shrub and tree cover increase by 0.3 (75%) and 0.03 (2%) million km 2 , respectively. The impacts of these vegetation shift on peatland carbon balance can be explored in future studies using the model, which integrates peatland vegetation dynamics with peatland‐specific hydrology and carbon cycling.

<strong class="journal-contentHeaderColor">Abstract.</strong> Strong spatial and temporal gradients in salinity, temperature, and carbonate chemistry in Arctic coastal surface waters complicate the estimation of air-sea CO₂ exchange, particularly during sea ice breakup. This study evaluates the applicability of the widely used bulk flux model under such conditions. The bulk approach assumes homogeneous surface conditions and linear vertical pCO₂ gradients. However, our observations in a stratified Arctic fjord reveal pronounced vertical variability in pCO₂ within the upper water column, including non-linear gradients near the air-sea interface. Micrometeorological measurements captured episodic upward CO₂ fluxes even when waters 1 m and below were CO₂-undersaturated. We hypothesize that transient, high-pCO₂ layers at ~0.1 m depth intermittently decouple the atmospheric exchange from subsurface waters, reversing the expected flux direction. These findings highlight the importance of resolving near-surface variability during the transition from ice-covered to open water conditions. We recommend incorporating micrometeorological techniques and high-resolution vertical profiling in Arctic fjords to improve flux estimates of CO₂ in this rapidly changing region.

Climate change is playing a major role in the current global biodiversity crisis. However, despite climate change being most pronounced in the Arctic, its impacts on biodiversity in this region remains largely unknown. Here, we combined three decades of abundance data from various animal groups (from zooplankton to megafauna) and regions in the European Arctic and Greenland to assess recent changes in biodiversity within Arctic coastal communities. Our results support the “borealization” hypothesis in all regions and provide evidence that marine ecosystems in the North Atlantic Arctic are shifting toward a boreal (i.e. cold temperate) state. Arctic endemic species are generally declining in abundance, while boreal species are increasing. These changes in abundance are associated with an average increase in biodiversity (e.g. species richness), although there are important variations among animal groups. This increase might be transient and the long-term implications of the ongoing changes in Arctic coastal biodiversity on ecosystem functioning and services remain uncertain.

Farmed kelp (Alaria esculenta and Saccharina latissima) can be the future North Atlantic Ocean crop, in coastal areas of Greenland, the Faroe Islands, and Norway. One of the main bottlenecks in upscaling kelp production is stabilising the annual harvest before it spoils. Microbial quality changes were investigated during chilled storage of seven and ten days for fresh A. esculenta and S. latissima, respectively, and subsequent stabilisation by either convection (37.2°C) or ambient temperature (range 5-10°C) atmospheric drying. The quality of the dried kelps was determined by their swelling, water-, and lipid-binding capacity. Microbial loads (3M Aerobic Count Plate) were 4.0-4.5 log(CFU/gwet weight) at harvest time for the two species and increased to 5.9-6.1 log(CFU/gwet weight) after seven days of storage at 2-3°C. For fresh kelp, which was immediately dried, both drying processes had a limited impact on the bacterial loads, with reductions of 0.3 to 2.0 log(CFU/gcorrected wet weight) during the process. In contrast, the same drying process resulted in reductions of 4.2 to 5.1 log(CFU/gcorrected wet weight) for kelp, which had been stored for seven days before drying. Dried S. latissima showed significantly higher swelling and water-binding capacities than A. esculenta, regardless of the drying method. Drying at ambient temperature over three days yielded higher lipid-binding capacity for both species than convection drying. Based on the bacterial concentrations, the seaweed should be stabilised within the first five days of post-harvest chilled storage. Convection drying inactivates more bacteria and has a shorter process time (2.5h). However, if the kelp is intended for use in a lipid-rich product like pesto, the slower ambient temperature drying might be beneficial.

The global ocean faces unprecedented challenges from overfishing, pollution, and climate change. The Central Arctic Ocean Fisheries Agreement is a rare, if not unprecedented, example of precautionary action in marine management. Further action is needed to address other forms of industrial activity in the region. Done well, this example can provide a model for sustainable ocean management around the world, based on sound evidence, inclusive governance, and long-term thinking.

Climate-driven changes in the Subarctic will directly impact capelin populations and the ecosystem they inhabit, including their predators, prey, and physical habitats. Consequently, incorporating ecosystem considerations in future capelin fisheries management is crucial. In this study, a multidisciplinary group of experts critically evaluated whether the current capelin stock assessment and management frameworks for the four main capelin stocks in the Barents Sea (BS), Iceland-East Greenland-Jan Mayen (IEGJM), Newfoundland and Labrador shelf (NL) and Alaska (AK) align with the principles of an Ecosystem Approach to Fisheries Management (EAFM). An evidence-based ranking of our knowledge on current capelin dynamics across ecological, economic, and social dimensions was conducted, using expert knowledge supported by literature. This exercise also identified data currently used for assessment and management, which highlighted that the existing capelin assessment frameworks include varying degrees of EAFM elements across stocks, such as considerations of trophic interactions, bottom-up processes, accounting for ecosystem uncertainty, and stakeholder engagement in the advisory process. Nonetheless, there is room for improvement where data and knowledge are lacking. We provide some key tactical (short-term) and strategic (long-term) recommendations from our perspective on what is required to ensure the sustainable management of capelin in the circumpolar region over the coming decades.

Studying adaptation to extreme climates is essential for understanding evolutionary processes and how species evolve and persist under changing environmental conditions, such as climate warming. Here, we investigate the genomic basis of adaptations in the Svalbard reindeer (Rangifer tarandus platyrhynchus), an endemic subspecies that colonized the High Arctic approximately 7,000 years ago and developed a suite of adaptations for survival under conditions of extreme cold, changes in day length, and resource scarcity. Applying scans of selection, functional analysis of coding region variation, and characterization of copy number variation across reindeer populations from Svalbard, mainland Norway, mainland Russia, and Novaya Zemlya, our comparative genomics approach identified 150 genomic regions that are differentiated in Svalbard reindeer relative to mainland reindeer (R. tarandus). These genomic regions include genes linked to fat metabolism, energy conservation, cold tolerance, body size, fur morphology, and seasonal circadian rhythm. Our study highlights the advantages of using distinct approaches to uncover the genomic basis of adaptations and provides a path for future research into the evolution of species in similar environments.

ABSTRACTGreenland sharks Somniosus microcephalus (Bloch & Schneider, 1801) are long‐lived and highly migratory animals distributed throughout deep and/or cold waters of the North Atlantic Ocean. Extensive bycatch in several demersal fisheries in the Arctic has raised conservation concerns for the species, of which surprisingly little is known about the spatial distribution in relation to their life history. In the current study, size, sex, and life stage composition of 1610 Greenland sharks were examined from 11 geographic regions across the northern North Atlantic Ocean. Subadult females dominated in most regions, and while adult females were scarce or absent in, for example, northern Arctic Canada and Svalbard, they dominated in southwest Greenland and Iceland. Furthermore, in southern Arctic Canada, northwestern Greenland, and southeastern Greenland, adult females were more commonly encountered in offshore waters than inshore. Depth (25 m to 1375 m) had little effect on the spatial distribution irrespective of length and life stage, whereas water temperatures (−1.54°C to 10.9°C) conclusively showed that adult females preferred warm water (> 4°C). Large juveniles were encountered in most regions but dominated in Skagerrak and in offshore southern Arctic Canada. Small juveniles and neonates were encountered with only five and zero records, respectively, combined for all analyzed regions. In an additional effort to identify these rare, small‐sized specimens, scrutinization of museum collections and databases of scientific institutions disclosed a cluster of ten neonates (total length < 60 cm) and two small juveniles (total length 60‐89 cm) along the mid‐Atlantic Ridge and the Irminger Sea. This finding is unique and suggests the location of a potential Greenland shark pupping ground on or in the vicinity of the mid‐Atlantic Ridge and Irminger Sea. All combined, this study provides new insights into the life history of the Greenland shark, which will aid the development of targeted conservation measures.

Freshwater fluxes entering fjords are important for ice-ocean interactions, &amp;#160;circulation in Greenland's fjords, and the use of freshwater forcing in ocean modelling. We study the timing, source type, and magnitude of freshwater fluxes and their temporal and spatial variability using statistically downscaled output from regional climate models for the mass fluxes, process-based estimates of basal melt and observational data for solid ice discharge. For seven climatologically distinct regions, we estimate the absolute and relative contribution of runoff from the Greenland Ice Sheet, ice caps, and tundra, solid ice discharge and precipitation directly falling into fjords between 1940 and 2023. The relative contribution of freshwater sources varies between months and regions, with distinct differences between the runoff-dominated southwest, and the solid-ice-discharge-dominated southeast.&amp;#160;