Svalbard Research Articles

Depth‐Related Controls on the Quantitative Composition of Rhodolith Matrices in the High Arctic

ABSTRACTThe calcareous matrix of rhodoliths can be composed of one or more crustose coralline algae (CCA) taxa as well as a mixed assemblage of various encrusting organisms. Studies on modern and fossil rhodoliths assume such associations to vary with water depth. Our study explores the quantitative biological composition of calcareous rhodolith matrices along a bathymetric gradient at the Arctic Svalbard archipelago. Using a methodological combination of virtual micro‐CT cross‐sections with a modified point counting approach, we found five different taxonomic groups: CCA, bivalves, serpulids, bryozoans and balanids. While water depth does not influence the general taxon richness as well as the abundance of bivalves, it significantly affects the proportional matrix composition of encrusting organisms by a combination of environmental factors and biological interactions. The decrease in CCA skeletal material with increasing water depth is significantly governed by impaired irradiance conditions. Regular rhodolith movement in shallow waters fosters the proportion of CCA, while decreased movement in deeper waters spurs the proportion of other encrusters. This potentially results from post‐mortem fouling of dead rhodolith parts followed by a recolonization with slow‐growing CCA species Boreolithothamnion glaciale. Our results highlight mechanisms controlling the biogenic composition of calcareous rhodolith matrices and underline the potential of matrices compositions for palaeogeography and palaeobathymetry. Our study contributes to an improved understanding of the composition and developmental patterns of rhodoliths. This can add to a better comprehension of the respective ecosystems on a broader scale and be beneficial for conservation purposes.

Metabarcoding the Arctic Ocean Helps Reveal Its Hidden Microbial Community Composition

The Arctic Ocean supports a unique and dynamic microbial community, yet its composition, structure, and response to environmental shifts remain incompletely understood. In this study, 16S rRNA gene metabarcoding (targeting the V3-V4 and V4-V5 hypervariable regions) was used to assess surface water microbial diversity across 20 stations in the Barents Sea, focusing on latitudinal variations within two contrasting current systems: the West Spitsbergen Current (WSC) and the East Spitsbergen Current (ESC). Our results showed that the microbial community is dominated by three primary families—Pseudoalteromonadaceae, Moraxellaceae, and Flavobacteriaceae (14.20%). Comparative analysis of the V3-V4 and V4-V5 regions reveals that each region captures different aspects of microbial diversity, with V4-V5 detecting a higher number of unique families. Analysis through Nonmetric Multidimensional Scaling (NMDS) reveals distinct community separations between the WSC and ESC, though ANOSIM results indicate no significant within-system differences. Environmental parameters, including pH and temperature, appear closely linked with community composition, reflecting the influence of climatic and oceanographic processes on microbial structure. As global climate change continues to reshape Arctic environments, monitoring microbial diversity is essential to understand and predict shifts in the Arctic Ocean`s ecosystem functions.

Marine Mammals Sightings at High Latitudes in the Barents Sea, the Northeastern Arctic

The Barents Sea, an important area for marine mammals, has changed due to climatic factors and increasing human activities. Information on the distribution of marine mammals and monitoring of areas of their high occurrence are essential for understanding population dynamics and informing conservation efforts. Survey data for occurrence of marine mammals were collected in the Barents Sea in the vicinity of the Svalbard Archipelago over 17 days in July, 2022 during the second multidisciplinary Turkish scientific Arctic expedition onboard the PolarXplorer. In total, 42 sightings of 6 cetacean species, 11 sightings of 4 pinniped species, and 2 sightings of polar bears (Ursus maritimus) were recorded during 110 hours of dedicated observation effort. White-beaked dolphins were sighted more often than the other cetacean species (χ2=30, P<0.05). The walrus was the most sighted species of pinnipeds. The encounter rate was 2.2 groups/100 nm for toothed whales, and 0.48-1.09 groups/100 nm for baleen whales. The sighted marine mammals mostly stayed as single individuals or pairs, while walruses were observed in groups of up to 120 individuals. Photo-identification data were collected and 35 humpback whale individuals were identified in the Arctic feeding area between 69.593973°N and 81.463930°N latitude; 5.443173°E and 36.833474°E longitude. Four individuals matched the existing records in the Happywhale catalogue. Our study contributes to the knowledge of occurrence and migration patterns of marine mammals in the Arctic region under rapid climate-mediated change.

The lost generation of Pemphigus populiglobuli (Hemiptera, Aphididae): exploring the taxonomy of the Svalbard aphids of genus Pemphigus

Species identification within the aphid genus Pemphigus Hartig, 1839 poses challenges due to morphological similarities and host-plant associations. Aphids of this genus generally exhibit complex life cycles involving primary hosts (poplars) and secondary (mostly unrelated herbaceous) host-plants, with some species relying solely on root-feeding generation. An example is a representative of the genus Pemphigus, trophically associated with grass roots, found in the High Arctic Svalbard archipelago. Historical records tentatively identify it as Pemphigus groenlandicus (Rübsaamen, 1898), although its formal classification remains elusive, due to limited material of freshly collected samples. Recent collections from 2007 to 2024 across various Svalbard sites, revealed its presence under stones in sheltered microhabitats, providing valuable specimens for comparative studies. Our molecular analyses indicate that the Svalbard specimens are not a separate species commonly identified as P. groenlandicus, nor an anholocyclic generation of Pemphigus bursarius (Linnaeus, 1758) or P. borealis Tullgren, 1909, but represent a secondary generation of Pemphigus populiglobuli Fitch, 1859, the Nearctic poplar bullet gall aphid. This suggests that they may have lost their primary host associations and adapted to living on grass roots year-round. Our specimens did not host any known facultative symbionts; however, we detected a strain of Pseudomonas Migula, 1894, closely related to a cold-tolerant bacterium abundant in polar regions. The present study also investigates the taxonomic relationships and morphometric characteristics of grass-feeding Pemphigus populations across the Arctic and an isolated locations on the European continent. Specimens from Svalbard were compared with samples from Greenland and Iceland, but identified no substantial morphometric differences among these geographically separated populations. Similarly, analyses of samples of Pemphigus groenlandicus crassicornis Hille Ris Lambers, 1952 from Sweden and Spain reveals a high morphometric similarity to the Arctic population, indicating a strong link between these traits and geographical variability. Despite the limitations in fresh material availability across locations, minor morphometric variations and shared ecological niches (all populations studied inhabiting grass roots, a unique trait within the Pemphigus genus) suggest treating both P. groenlandicus and its subspecies crassicornis as a junior synonym to P. populiglobuli. The study also demonstrates that the secondary generation of P. populiglobuli is a terrestrial microarthropod that overwinters in a postembryonic life-stage in situ in soil and vegetation under harsh Arctic conditions, and its cryptic life complicates its distribution mapping.

SEISMICITY of the ARCTIC in 2020

The article provides an overview and analysis of seismicity within the boundaries of the Arctic region for 2020 based on a consolidated catalog of earthquakes compiled from catalogs of the N. Laverov Federal Center for Integrated Arctic Research of the Ural Branch of the Russian Academy of Sciences, the Kola and Ya kutsk branches of the Geophysical Survey of the Russia Academy of Sciences (GS RAS), using data from the Seismological Bulletin of the GS RAS and the International Seismological Center. A total of 475 earthquakes are included in the consolidated catalog for 2020. Most of the earthquakes that occurred in 2020, including all the strongest earthquakes, were located within the mid-ocean ridges of Mon, Knipovich. Gakkel and Spitsbergen Fault Zone. In the offshore territories, most of the earthquakes were confined to the Svalbard archipelago, in particular, to the seismically active zone in the Sturfjord strait. Within the shelf areas, seismicity is also characteristic of the Novaya Zemlya archipelago, "continent-ocean" transition zone of the Barents-Kara region, Bely (Kvitøya) and Bear (Bjørnøya) Islands. For 17 earthquakes, the focal mechanism parameters are presented according to the Global CMT catalog.

A study on the growth of the unstalked crinoid <i>Heliometra glacialis</i> (Owen 1833 ex Leach MS) (Echinodermata, Crinoidea) based on ring-shaped bands formed in the brachials

The growth of the unstalked crinoid Heliometra glacialis was studied based on material from the northwestern part of the Barents Sea near the Svalbard Archipelago. The calculation of the crinoid age was performed using ring-shaped markings in the their brachials. The growth rings visible on the surface of the crinoid brachials were considered as annual. The most suitable mathematical model describing the growth of H. glacialis was the Gompertz equation. The averaged limiting radius of the brachials (R∞), according to this equation, was 1694 ± 119 microns, the exponential deceleration constant of the specific growth rate (g) amounted to 0.41 ± 0.04, and the maximum lifespan to 12–18 years.

Heterologous Production, Purification and Characterization of Two Cold-Active β-d-Galactosidases with Transglycosylation Activity from the Psychrotolerant Arctic Bacterium Arthrobacter sp. S3* Isolated from Spitsbergen Island Soil.

Cold-adapted microorganisms possess cold-active enzymes with potential applications in different industries and research areas. In this study, two genes encoding β-d-galactosidases belonging to Glycoside Hydrolase families 2 and 42 from the psychrotolerant Arctic bacterium Arthrobacter sp. S3* were cloned, expressed in Escherichia coli and Komagataella phaffii, purified and characterized. The GH2 β-d-galactosidase is a tetramer with a molecular weight of 450 kDa, while the GH42 β-d-galactosidase is a 233 kDa trimer. The Bgal2 was optimally active at pH 7.5 and 22 °C and maintained 57% of maximum activity at 10 °C, whereas the Bgal42 was optimally active at pH 7.0 and 40 °C and exhibited 44% of maximum activity at 10 °C. Both enzymes hydrolyzed lactose and showed transglycosylation activity. We also found that 2 U/mL of the Bgal2 hydrolyzed 85% of lactose in milk within 10 h at 10 °C. The enzyme synthesized galactooligosaccharides, heterooligosaccharides, alkyl galactopyranosides and glycosylated salicin. The Bgal42 synthesized galactooligosaccharides and 20 U/mL of the enzyme hydrolyzed 72% of milk lactose within 24 h at 10 °C. The properties of Arthrobacter sp. S3* Bgal2 make it a candidate for lactose hydrolysis in the dairy industry and a promising tool for the glycosylation of various acceptors in the biomedical sector.

Stratigraphic chronology and mechanisms of formation of bottom sediments at the mouth of the Grøndalen River (Grøn-Fjord, West Spitsbergen) during the period of climatic changes

The results of the study of bottom sediments and water of the estuary of the River Grøndalen (Grøn-fjord, West Spitsbergen) are presented. The stratigraphic features of the sedimentary strata are determined. The chronology of changes in geoecological environmental conditions has been established using radioisotope dating methods. The main factors influencing sedimentation in the study area are air temperature and precipitation during the period of predominance of low temperatures. It is shown that climate fluctuations determine the chronological sequence of the sedimentation rate and the change of the lithotype of the bottom sediment towards fine fractions.

PRA Melting-ICE Project: Svalbard 2022 Expeditions Report

Arctic regions are among the fastest warming areas of the planet. Increasing average temperatures over the last five decades have deepened the thawing of the upper-most layer of permafrost across the Arctic, which contains significant amounts of organic carbon. The progressive deepening of seasonal thawing releases carbon that is used by active microorganisms which also produce greenhouse gases, potentially onsetting a positive feedback on global warming. Despite their importance in controlling organic matter degradation and greenhouse gas fluxes to the atmosphere, there is a lack of data on activity and dynamics of microbial communities in High Arctic soils in response to seasonal thaw. This report describes three specific expeditions performed on the Svalbard archipelago, carried out within the framework of the PRA (Italian Arctic Research Program) project Melting-ICE, performed between February and October 2022, reporting site characteristics and samples collected. The project aims to investigate the diversity and activity of active layer microbial communities across a full season thaw cycle, correlating microbial diversity with gas fluxes and composition. During these expeditions, a total of eight different sites were selected to investigate the microbiology and geochemistry of soils, as well as to estimate the gas fluxes from the soil to the atmosphere. The data collected in the field, combined with the results obtained in the laboratory, will provide a snapshot of the seasonal activity of the microbial communities present in the permafrost’s active layer. The three campaigns will provide data to estimate the impact of permafrost melting on the carbon cycle and the role of microorganisms in the release of greenhouse gases.

Genetic variation within the arctic-alpine Calamagrostis stricta (Poaceae) species complex in Europe

The Calamagrostis stricta (Poaceae) species complex is a circumpolar, boreo-arctic and montane taxon that includes numerous subspecies and varieties. The recent discovery of Calamagrostis lonana in the Alps calls for a thorough assessment of relationships within C. stricta. The main aim of our study was to elucidate the phylogenetic position, genetic structure and ploidy level of C. lonana, as compared to the other members of the C. stricta species complex from Central Europe to the Arctic. Fifteen populations of the C. stricta species complex were sampled across Central and Northern Europe, and their ploidy level was estimated using flow cytometry. Genetic variation was characterized using double digest RAD sequencing reads (ddRAD-seq) on a total of 115 individuals genotyped at 1157 single-nucleotide polymorphisms. Based on flow cytometric measurements, tetraploidy was observed in Arctic populations from Northern Europe and C. lonana in the Alps, in contrast to other populations exhibiting higher ploidy levels. Calamagrostis lonana was genetically closely related to the arctic C. stricta subsp. groenlandica, while C. stricta subsp. stricta formed a second genetic cluster across Central Europe. A third, very distinct genetic cluster was observed in the northern Svalbard archipelago. Despite lacking evidence of sexual reproduction, substantially more genetic diversity than expected under asexual reproduction was detected within populations in C. lonana and other taxa. The distribution and genetic structure of the C. stricta species complex has been shaped by major post-glacial environmental changes having affected cold regions and specifically highlights C. lonana as a valuable relict taxon for the Alps.

The Arctic front of the global hybrid warfare

The role and significance of the Arctic in international relations of the late 20th and early 21st centuries have undergone serious changes, and so have their assessments in the academic literature. To date, the Arctic has already turned into the scene of bitter international rivalry, albeit not yet a theater of military operations. In order to provide a better understanding of the scale, dynamics, and potential consequences of these developments, the author examines them through the lens of the hybrid warfare concept. The first section provides a thorough review of the key approaches to the definition of the hybrid warfare and its specific features. The author pays special attention to the NATO’s theoretical advances in the methods of the hybrid warfare and their practical implementation in the Arctic region. The second section examines the specific forms and manifestations of hybrid warfare in the Transarctic. The researcher notes that the population of the islands of Svalbard and Wrangel is exposed to a remarkably large-scale hostile hybrid influence from the NATO countries, and concludes that Russophobic narratives peddled to the peoples of the Subarctic pose a serious risk to regional stability. The author argues that in order to counter hybrid threats from the collective West, Russia needs to develop a comprehensive Arctic strategy. The latter should include, inter alia, an effective system for monitoring geopolitical threats not only against Russia, but also against its BRICS+, SCO, EAEU, CSTO partners; measures to strengthen cooperation with Eurasian, international and intergovernmental structures and business communities unyielding against sanctions pressure; programs for the development of indigenous peoples aimed at preserving their civilizational identity.

Sources and Seasonal Variations of Per- and Polyfluoroalkyl Substances (PFAS) in Surface Snow in the Arctic.

Per- and polyfluoroalkyl substances (PFAS) are persistent anthropogenic contaminants, some of which are toxic and bioaccumulative. Perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) can form during the atmospheric degradation of precursors such as fluorotelomer alcohols (FTOHs), N-alkylated perfluoroalkane sulfonamides (FASAs), and hydrofluorocarbons (HFCs). Since PFCAs and PFSAs will readily undergo wet deposition, snow and ice cores are useful for studying PFAS in the Arctic atmosphere. In this study, 36 PFAS were detected in surface snow around the Arctic island of Spitsbergen during January-August 2019 (i.e., 24 h darkness to 24 h daylight), indicating widespread and chemically diverse contamination, including at remote high elevation sites. Local sources meant some PFAS had concentrations in snow up to 54 times higher in Longyearbyen, compared to remote locations. At a remote high elevation ice cap, where PFAS input was from long-range atmospheric processes, the median deposition fluxes of C2-C11 PFCAs, PFOS and HFPO-DA (GenX) were 7.6-71 times higher during 24 h daylight. These PFAS all positively correlated with solar flux. Together this suggests seasonal light is important to enable photochemistry for their atmospheric formation and subsequent deposition in the Arctic. This study provides the first evidence for the possible atmospheric formation of PFOS and GenX from precursors.

Spatial Distribution and Growth Patterns of a Common Bivalve Mollusk (Macoma calcarea) in Svalbard Fjords in Relation to Environmental Factors.

Ongoing warming in the Arctic has led to significant sea-ice loss and alterations in primary production, affecting all components of the marine food web. The considerable spatial variability of near-bottom environments around the Svalbard Archipelago renders the local fjords promising sites for revealing responses of benthic organisms to different environmental conditions. We investigated spatial variations in abundance, biomass, and growth parameters of the common bivalve Macoma calcarea in waters off western Spitsbergen and identified two distinct groups of this species: one composed mainly of cold-water stations from Storfjorden (Group I) and the other comprising warmer-water stations from Grønfjorden and Coles Bay (Group II). Within these groups, the mean abundance, biomass, production, and mortality accounted for 0.2 and 429 ind. m-2, 20 and 179 g m-2, 18.5 and 314 g m-2 year-1, and 0.22 and 0.10 year-1 respectively. The size-frequency and age-frequency distributions were biased towards smaller and younger specimens in Group I, while Group II displayed more even distributions. The maximum ages were 11 and 21 years, respectively. The mollusks from cold water were significantly smaller than their same-aged counterparts from warmer water. Two groups of Macoma were identified: slow-growing individuals with a rate of 1.4 mm and fast-growing individuals with a growth rate of 1.8 mm. Most population parameters were higher than those observed in the Pechora, Kara, and Greenland Seas. Redundancy analysis indicated water temperature as the main driving factor of abundance and biomass, while the latter was also influenced by the presence of pebbles. Our findings provide new insights into the growth patterns and spatial distribution of Macoma at high latitudes and confirm that this species can serve as a reliable indicator of environmental conditions.

Increased Concentrations of Dopamine in the Blood and the State of the Immune System in Practically Healthy Residents of the Northern Territories

The numerous effects of dopamine are predetermined by the fact that it, being a chemical precursor of noradrenaline, is secreted in nervous tissue, in the adrenal medulla, kidneys, intestines, and APUD cells (Apudocytes). The purpose of the work is to study the effectiveness of immune reactions at elevated concentrations of dopamine in the blood of practically healthy residents of the northern territories. The results of an immunological examination of 1064 practically healthy people aged 25-55 years living in the Arkhangelsk and Murmansk regions, as well as in the Nenets Autonomous Okrug, the Komi Republic and the Svalbard archipelago (Barentsburg) were analyzed. It was found that elevated concentrations of dopamine in peripheral venous blood were more often recorded in Arctic residents; during the polar day, dopamine concentrations are higher than in winter. Increased concentrations of dopamine in the blood of Northerners are associated with a decrease in the level of activated T cells with the transferrin receptor and IL-2, T-helper cells, as well as with increased concentrations of IL-1β, TNF-α, cortisol and thyroxine. An increase in dopamine concentration may be a consequence of a cytokine reaction in the nervous tissue to inhibit excessive receptor activity of cells by increasing the concentration of IL-10. The formation of an excess of both central hormones secreted by the pituitary gland and peripheral hormones at the same time is probably due to an increase in the sensitivity threshold of the hypothalamus, which is associated with an increase in the flow of interoceptive impulses of afferent systems.

Linking PVA models into metamodels to explore impacts of declining sea ice on ice-dependent species in the Arctic: the ringed seal, bearded seal, polar bear complex

Arctic ecosystems are especially vulnerable to the impacts of climate change because of the limit to possible northward shifts for species dependent on land or continental shelf and because the rate of warming of the region has been 2-4 x the global average in recent decades. The decline in sea ice in the Arctic has both direct and indirect impacts on the species that live in association with ice, breeding on it, traveling over it, feeding on other ice-dependent species or avoiding competition with subarctic species that cannot exploit resources in ice-covered areas. Herein, we present a metamodel of a top-level predator, the polar bear (Ursus maritimus), and two of its key prey species, ringed seals (Pusa hispida) and bearded seals (Erignathus barbatus), which are important in maintaining current polar bear densities and in turn are strongly influenced by bear predation. We used a metamodel that links Population Viability Analyses of the three species in order to examine how the impacts of declining spring land-fast sea ice on the fjords of Svalbard (Norway) and Frans Josef Land (Russia) can cascade through this predator-prey system. As the ice conditions that allow ringed seals to raise pups in snow-covered lairs on the frozen fjords diminish, or even disappear, ringed seal populations using the land-fast sea ice will collapse due to lack of successful recruitment. Consequently, the polar bear population, which relies heavily on hunting ringed seals in the land-fast sea ice to be able to raise their own offspring is also likely to decline. Our models suggest time-lags of decades, with the polar bear population not entering into decline until the lack of recruitment of ringed seals results in the depletion of breeding age ringed seals – starting in the third decade from the start point of the model and dropping below the initial population size only some decades later. Although lags between climate change and impacts on the ice-associated fauna are expected, the sea ice conditions have already changed dramatically in the northern Barents Sea region, including the Svalbard Archipelago, and the collapse of this Arctic species assemblage might already be underway.

Seasonality and interannual variability of an arctic marine time series, IsA

The Arctic is warming twice as fast as anywhere else on the planet, in the European Arctic mainly driven by exalted Atlantic Water inflow. Microbial eukaryotes are diverse and essential to the functioning of marine ecosystems, thus environmental perturbations altering their communities influence the entire ecosystem. To study seasonal and interannual variation and the potential effects of Atlantification, a long-term marine time series has been established in Isfjorden-Adventfjorden (IsA), West Spitsbergen. We here present three years of high-resolution data including hydrography, nutrients, photosynthetic biomass, flow cytometry and community composition of microbial eukaryotes (0.45–10μm, based on Illumina metabarcoding of 18S rDNA and rRNA). The timing, magnitude and species composition of the spring bloom varied interannually, with the more Atlantic spring 2014 being distinctly different from the two other years. A strong recurring seasonal pattern was evident in biodiversity, cell abundances and community composition. Winter communities were characterized by high alpha diversity and very low cell numbers with a dominance of heterotrophic and parasitic taxa. Despite large intra- and interannual differences in communities during the productive time of the year, winter communities were always highly similar, suggesting that the polar night represents a strong environmental forcing that resets the microbial communities.

In-situ observations of gelatinous zooplankton aggregations in inshore and offshore Arctic waters

Gelatinous zooplankton (GZ), play a crucial role in marine food webs, nutrient cycling, and carbon sequestration, however, quantifying their abundances remains challenging due to their delicate body structure, complex life cycles and variable population dynamics. Their tendency to form sporadic, large-scale aggregations further complicate the differentiation between true ecosystem alterations and stochastic variations in their abundance. In the Arctic Ocean, our understanding of GZ aggregations remains generally incomplete. Using in-situ observations from a towed pelagic camera system, we assessed the diversity and vertical distributions of GZ in fjord and offshore environments in northern Norway and the Svalbard archipelago. We found that Atlantic water masses harbored the highest GZ abundance, while intermediate waters showed the highest diversity. We documented dense aggregations of Beroe spp. in Van Mijenfjorden in Svalbard (observed during ascent of the camera system, not quantified in ind. m−3) and Bolinopsis infundibulum in the open Barents Sea (> 2.67 ind. m−3 at 100 m). Other observed taxa included the hydrozoans Aglantha digitale, Melicertum octocostatum, Solmundella bitentaculata, Pandeidae sp. and Physonectae spp., the scyphozoan Cyanea capillata and the ctenophores Mertensia ovum and Euplokamis sp. By linking the vertical distribution and observations of local aggregations with physical and biotic factors, we described the potential drivers of the distributional patterns observed. Towed camera surveys contribute to accurate in-situ observations, thereby improving our understanding of GZ aggregations and distributions in the Arctic Ocean.

Emergence of Potential Anadromous Arctic Charr (Salvelinus alpinus) Habitats in the Svalbard Archipelago After the End of the Little Ice Age

AbstractGlaciers in the Svalbard Archipelago are retreating rapidly in response to climate change. This retreat leads to the alteration of the hydrological and thermal regimes of freshwater ecosystems. In this delicate context, existing anadromous Arctic charr (Salvelinus alpinus) populations are at severe risk and might disappear from the archipelago. However, the retreat of glaciers also promotes the formation of new lake systems that might be suitable for colonization by anadromous Arctic charr. These systems may provide a substantial opportunity for the establishment of new populations of anadromous charr, potentially buffering the decline in existing systems. To date, there is a lack of information on the number of recently deglaciated lake systems that have emerged since the end of the Little Ice Age (ca. 1920) that might be suitable for charr colonization. Therefore, the goal of this paper is to provide an initial assessment of the number of these lakes. To this end, and in accordance with previously published research, this study assesses whether a recently deglaciated lake system is potentially open to colonization based on gradient, river length, and lake surface area. Depending on the applied threshold (four in total), up to 24 lake systems are classified as potentially open to colonization by anadromous Arctic charr, with Spitsbergen emerging as a potential hotspot for colonization. The findings of this paper might serve as basis for new studies and for implementing proactive management and conservation strategies to protect anadromous charr populations.

The Upper Devonian to Lower Carboniferous Billefjorden Group on Bjørnøya, Svalbard, and Its North‐Eastern Greenlandic Provenance

ABSTRACTIn this contribution, we document changes in detrital zircon ages in the upper Devonian (Famennian) to lower Carboniferous (Mississippian) Billefjorden Group on Bjørnøya, the southernmost island of Svalbard. This alluvial, coal‐bearing clastic succession is widely distributed across the archipelago and the Barents Shelf. The sediments were deposited in subsidence‐induced lowlands that formed just after regional post‐Caledonian collapse‐related extension, which created the classical ‘Old Red Sandstone’ basins during the Devonian, and prior to localised rift‐basin development in the middle Carboniferous (Serpukhovian–Moscovian). Moreover, the succession is little affected by Ellesmerian compressional deformation, which occurred in the latest Devonian. However, little is known of the provenance and regional sediment routing in this tectonically transitional period between the post‐Caledonian structuring events in the Devonian and the middle Carboniferous rifting. It has previously been invoked that a regional fault running parallel to the western Barents Shelf margin, the West Bjørnøya Fault, controlled sedimentation in the area. Here, we combine detrital zircon U–Pb ages and sedimentological data to investigate stratigraphic provenance variations and test whether tectonics controlled deposition of the Billefjorden Group on Bjørnøya. Sedimentological investigations demonstrate changes in fluvial style with intercalations between successions dominated by meandering channel fills and abundant overbank fines to sandstone‐dominated sheet‐like successions of braided stream origin. Palaeocurrent data show that two competing drainage directions accompany the changes in fluvial architecture. Northeasterly transport directions, recorded in the braided stream deposits, indicate possible fault‐transverse drainage. The detrital zircon content in these deposits indicates sourcing from Caledonian terranes in Northeast Greenland. Northwest‐oriented transport directions, measured in the meandering channel deposits, are inferred to represent axially positioned drainage systems. These may have been sourced from either Northeast Greenland, a more localised source, or Baltica. The latter would require long‐distance sourcing, which, given the tectonic setting of the region, seems unlikely. Although our sedimentological observations point to syn‐tectonic deposition, this is not clearly captured in the detrital zircon data, suggesting a common source for the Late Devonian–Mississippian fluvial systems of Bjørnøya. Thus, combined with previously published provenance data from Svalbard and Greenland, we demonstrate that the East Greenland Caledonides formed a long‐lived and significant source area which provided sediments to nearby basins from the Devonian to the Early Cretaceous.

Mastering Snow Analysis: Enhancing Sampling Techniques and Introducing ACF Extraction Method with Applications in Svalbard.

Semi-volatile organic contaminants (SVOCs) are known for their tendency to evaporate from source regions and undergo atmospheric transport to distant areas. Cold condensation intensifies dry deposition, particle deposition, and scavenging by snow and rain, allowing SVOCs to move from the atmosphere into terrestrial and aquatic ecosystems in alpine and polar regions. However, no standardized methods exist for the sampling, laboratory processing, and instrumental analysis of persistent organic pollutants (POPs) in snow. The lack of reference methods makes these steps highly variable and prone to errors. This study critically reviews the existing literature to highlight the key challenges in the sampling phase, aiming to develop a reliable, consistent, and easily reproducible technique. The goal is to simplify this crucial step of the analysis, allowing data to be shared more effectively through standardized methods, minimizing errors. Additionally, an innovative method for laboratory processing is introduced, which uses activated carbon fibers (ACFs) as adsorbents, streamlining the analysis process. The extraction method is applied to analyze polychlorobiphenyls (PCBs) and chlorinated pesticides (α-HCH, γ-HCH, p,p'-DDE, o,p'-DDT, HCB, and PeCB). The entire procedure, from sampling to instrumental analysis, is subsequently tested on snow samples collected on the Svalbard Islands. To validate the efficiency of the new extraction system, quality control measures based on the EPA methods 1668B and 1699 for aqueous methods are employed. This study presents a new, reliable method that covers both sampling and lab analysis, tailored for detecting POPs in snow.