Arctic Archipelago Of Svalbard Research Articles

Arctic plasmidome analysis reveals distinct relationships among associated antimicrobial resistance genes and virulence genes along anthropogenic gradients.

Polar regions are relatively isolated from human activity and thus could offer insight into anthropogenic and ecological drivers of the spread of antibiotic resistance. Plasmids are of particular interest in this context given the central role that they are thought to play in the dissemination of antibiotic resistance genes (ARGs). However, plasmidomes are challenging to profile in environmental samples. The objective of this study was to compare various aspects of the plasmidome associated with glacial ice and adjacent aquatic environments across the high Arctic archipelago of Svalbard, representing a gradient of anthropogenic inputs and specific treated and untreated wastewater outflows to the sea. We accessed plasmidomes by applying enrichment cultures, plasmid isolation and shotgun Illumina sequencing of environmental samples. We examined the abundance and diversity of ARGs and other stress-response genes that might be co/cross-selected or co-transported in these environments, including biocide resistance genes (BRGs), metal resistance genes (MRGs), virulence genes (VGs) and integrons. We found striking differences between glacial ice and aquatic environments in terms of the ARGs carried by plasmids. We found a strong correlation between MRGs and ARGs in plasmids in the wastewaters and fjords. Alternatively, in glacial ice, VGs and BRGs genes were dominant, suggesting that glacial ice may be a repository of pathogenic strains. Moreover, ARGs were not found within the cassettes of integrons carried by the plasmids, which is suggestive of unique adaptive features of the microbial communities to their extreme environment. This study provides insight into the role of plasmids in facilitating bacterial adaptation to Arctic ecosystems as well as in shaping corresponding resistomes. Increasing human activity, warming of Arctic regions and associated increases in the meltwater run-off from glaciers could contribute to the release and spread of plasmid-related genes from Svalbard to the broader pool of ARGs in the Arctic Ocean.

MtDNA data reveal disparate population structures and High Arctic colonization patterns in three intertidal invertebrates with contrasting life history traits

IntroductionPost-glacial climate variation is known to have influenced the distribution of marine species in the North Atlantic. In particular, the Atlantic side of the Arctic has experienced strong fluctuations in both atmospheric and sea surface temperature, as well as seasonal ice coverage since the last glacial maximum (LGM). Here, we aim to unveil the phylogeography and historical demography of three rocky intertidal marine invertebrates showing a trans-Atlantic distribution and presently inhabiting the Arctic: Gammarus oceanicus, Littorina saxatilis and Semibalanus balanoides.MethodsWe used a large amount of mitochondrial DNA barcode data, both newly-obtained and stored in public databases. We performed phylogeographic and demographic analyses on 1119 G. oceanicus, 205 L. saxatilis, and 884 S. balanoides sequences.ResultsOur results show that all three of these boreal species have expanded their effective population sizes in the high Arctic Svalbard Archipelago since the LGM. Analyses investigating the origin of all these populations point to the eastern Atlantic.DiscussionBased on our results we conclude that the expansion of these boreal species to the Arctic possibly happened during an earlier warm cycle of the Holocene era, and is probably not the result of the recent ‘Atlantification’ of the Arctic. We also discuss the effects of dispersal potential on population structure as an important aspect of comparative biogeographical studies.

Arctic cooperation between Norway and Russia in healthcare delivery and emergency preparedness on Svalbard: barriers and facilitators

ABSTRACT This interdisciplinary study explores whether increased cooperation in healthcare delivery and emergency preparedness between Norway and Russia on the Arctic archipelago Svalbard may increase the quality of these services and whether cooperation is desired. Ten semi-structured interviews were conducted and the respondents were asked to describe the current cooperation. Further, they were questioned about what they considered the main facilitators and the main barriers to cooperation. By analyzing the results, the study explores these facilitators and barriers and identifies how healthcare delivery and emergency preparedness are organized on Svalbard. Moreover, the study detects potential areas of cooperation within the given field, and the desire for such cooperation. The findings show that there are both facilitators and barriers regarding cooperation in healthcare delivery and emergency preparedness. Main facilitators include mutual trust, shared challenges, and existing administrative structures, equipment, and infrastructure. The main barriers involve differences in language and culture, high personnel turnover, and divergent systems for emergency preparedness on the Norwegian and Russian mainland. Mine rescue, emergency preparedness, and joint exercises focusing on health challenges are areas where Norway and Russia may cooperate in the future.

Svalbox Digital Model Database: A geoscientific window into the High Arctic

Abstract Digital outcrop models (DOMs) have revolutionized the way twenty-first century geoscientists work. DOMs are georeferenced three-dimensional (3-D) digital representations of outcrops that facilitate quantitative work on outcrops at various scales. Outcrop digitalization has been traditionally conducted using laser scanners, but in the past decade, it has seen an exponential growth because of efficient and consumer-friendly structure-from-motion (SfM) algorithms concurrent with the rapid development of cost-effective aerial drones with high-resolution onboard cameras. While DOMs are routinely used in geoscientific research, education, and industry, enhanced DOM usage is restricted because raw data (e.g., photographs) and metadata are often incomplete and/or unavailable. In this contribution, we present the Svalbox Digital Model Database (Svalbox DMDb), a database of metadata and openly available data packages for individual DOMs. The Svalbox DMDb is a regional DOM database geographically constrained to the Norwegian High Arctic archipelago of Svalbard at 74°N–81°N and 10°E–35°E. Svalbard offers exceptional-quality, vegetation-free outcrops with a wide range of lithologies and tectono-magmatic styles, including extension, compression, and magmatism. Data and metadata of the systematically digitalized outcrops across Svalbard are shared according to FAIR principles through the Svalbox DMDb. Fully open-access and downloadable DOMs include not just the DOMs themselves, but also the input data, processing reports and projects, and other data products such as footprints and orthomosaics. Rich metadata for each DOM include both the technical and geological parameters (metadata), enabling visualization and integration with regional geoscientific data available through the Norwegian Polar Institute and the Svalbox online portal. The current release of Svalbox DMDb, documented in this contribution, covers 135 DOMs cumulatively covering 114 km of Proterozoic to Cenozoic stratigraphy.

The impact of marine vertebrates on polar terrestrial invertebrate communities

AbstractMarine birds and pinnipeds which come to land to breed, rest and moult are widely known to fertilize adjacent terrestrial ecosystems, with cascading effects on vegetation and other trophic levels. We provide a synthesis of the consequences of allochthonous nutrient enrichment for terrestrial invertebrate communities within and around marine vertebrate aggregation sites and nutrient sources in the High Arctic and Continental and Maritime Antarctic, the most nutrient-poor and environmentally extreme parts of the polar regions. Using a combination of literature review (identifying 19 articles from the Arctic Svalbard archipelago and 12 from different Antarctic locations) and new analyses of available datasets of springtail, mite and tardigrade community composition, we confirmed that terrestrial invertebrate abundance and species richness tended to increase, and their community compositions changed, as a result of marine vertebrate fertilisation in both polar regions. These changes were significantly greater on talus slopes enriched by kittiwakes, guillemots and little auks in the Arctic, as compared to the edges of penguin colonies in the Antarctic. Both these habitat areas were typically abundantly vegetated and provided the most favourable microhabitat conditions for terrestrial invertebrates. The most heavily disturbed and manured areas within Antarctic penguin rookeries and seal wallows, generally on flat or gently sloping ground, were typically characterised by extremely low invertebrate diversity. In the Arctic, only sites directly beneath densely-occupied bird cliffs were to some extent comparably barren. Invertebrate responses are dependent on a combination of vertebrate activity, local topography and vegetation development.

From everywhere all at once: Several colonization routes available to Svalbard in the early Holocene.

For many arctic species, the spatial (re-)colonization patterns after the last Pleistocene glaciation have been described. However, the temporal aspects of their colonization are largely missing. Did one route prevail early, while another was more important later? The high Arctic archipelago Svalbard represents a good model system to address timeframe of postglacial plant colonization. Svalbard was almost fully glaciated during last glacial maximum and (re-)colonization of vascular plants began in early Holocene. Early Holocene climatic optimum (HCO) supported an expanded establishment of a partly thermophilic vegetation. Today, we find remnants of this vegetation in sheltered regions referred to as "Arctic biodiversity hotspots". The oldest record of postglacial plant colonization to Svalbard is found in Ringhorndalen-Flatøyrdalen. Even though thermophilic species could establish also later in Holocene, only HCO was favorable for vast colonization, and only hotspots offered stable conditions for thermophilic populations throughout Holocene. Thus, these relic populations may reflect colonization patterns of HCO. We investigate whether the colonization direction of thermophilic plants (Arnica angustifolia, Campanula uniflora, Pinguicula alpina, Tofieldia pusilla, and Vaccinium uliginosum ssp. microphyllum) in Ringhorndalen-Flatøyrdalen was uniform and different from later colonization events in other localities and non-thermophilic plants (Arenaria humifusa, Bistorta vivipara, Juncus biglumis, Oxyria digyna, and Silene acaulis). We analyzed plastid haplotypes of the 10 taxa from Ringhorndalen-Flatøyrdalen, from later-colonized localities in Svalbard, and from putative source regions outside Svalbard. Only rare and thermophilic taxa Campanula uniflora and Vaccinium uliginosum ssp. microphyllum provided results suggesting at least two colonization events from different source regions. Tofieldia pusilla and all the non-thermophilic plants showed no clear phylogeographically differentiation within Svalbard. Two of the thermophilic species showed no sequence variation. Based on the results, a uniform colonization direction to Svalbard in early Holocene is not probable; several source areas and dispersal directions were contemporarily involved.

West Spitsbergen fold and thrust belt: A digital educational data package for teaching structural geology

The discipline of structural geology is taking an advantage of compiling observations from multiple field sites to comprehend the bigger picture and constrain the region's geological evolution. In this study we demonstrate how integration of a range of geospatial digital data sets that relate to the Paleogene fault and thrust belt exposed in the high Arctic Archipelago of Svalbard, is used in teaching in bachelor-level courses at the University Centre in Svalbard. This event led to the formation of the West Spitsbergen Fold and Thrust Belt and its associated foreland basin, the Central Spitsbergen Basin. Our digital educational data package builds on published literature from the past four decades augmented with recently acquired high-resolution digital outcrop models, and 360° imagery. All data are available as georeferenced data containers and included in a single geodatabase, freely available for educators and geoscientists around the world to complement their research and fieldwork with course components from Svalbard.

The Svalbard treaty and identity of place: Impacts and implications for Longyearbyen, Svalbard

Abstract The Svalbard Treaty established Norway’s full and absolute sovereignty over the Arctic archipelago of Svalbard. At the same time, it also established special territorial status for the archipelago, providing nationals of all signatory nations equal access to its resources. During fieldwork in Longyearbyen, conducted as part of a bottom-up exploration of place in 2018, several recurring issues came up in the analysis of interviews with residents using grounded theory methodology. Two of these issues, sometimes linked and sometimes seen as separate, were a questioning of the legitimacy of the community and a sense of geopolitical vulnerability. These emerging categories led to a series of focus groups, conducted between December 2018 and November 2019, that was designed to explore the impacts and implications of the Svalbard Treaty through the articulation of residents’ lived experiences in Longyearbyen. This paper examines the findings that emerged within an Identity of Place framing that point to an inherent conflict between the Svalbard Treaty’s special territorial status and the possibility of establishing a fully functioning local democracy in Longyearbyen.

The figure of the guide: arctic nature guiding as productive behaviour on Svalbard

Abstract Drawing from ethnographic participation in a ski excursion among a group of Arctic Nature Guide students on the Arctic archipelago of Svalbard, this paper explores guiding as a model of practice embedded in relations – material encounters, discursive frictions and collaborative efforts. The article pays attention to practical negotiations and navigations of these relations while making use of historical scholarship on the role of the guide as a basis for theoretical reflections on the role’s mediation activities. More precisely, the paper advocates a “creation-model of mediation” that challenges modernist representational discourse (and conceptualisations of nature) through a recognition of guiding as productive behaviour. Displaying agency in meaning-making and embodying Svalbard’s transient cosmopolitan population, the guide emerges as a figure on ground far from fixed and settled, and as a tool with which to appraise Svalbard as more geo-aesthetical condition than bounded place.

CORTISOL LEVEL AND Na<sup>+</sup>/K<sup>+</sup>-ATPASE ACTIVITY DURING GROWTH AND DEVELOPMENT OF JUVENILE DAUBED SHANNY <i>LEPTOCLINUS MACULATUS</i> (FRIES, 1838) IN THE ARCTIC

The dynamics of cortisol level and Na+/K+-ATPase (NKA) activity that are associated with the maintenance of cell ion homeostasis was studied in skeletal muscles of juvenile circumpolar fish daubed shanny Leptoclinus maculatus (Fries, 1838), an ecologically significant representative of the ichthyofauna of the Arctic Svalbard archipelago. It has been established that the level of cortisol and NKA activity decrease during the development of daubed shanny juveniles from L2 stage pelagic juveniles of L5 stage, which are mainly demersal. The results obtained suggest that cortisol may be involved in the regulation of the activity of one of the main osmoregulatory factors, NKA. This may be important for the growth and adaptation of pelagic juveniles of daubed shanny to the demersal habitat during postembryonic development in the Arctic.

Cortisol Level and Na+/K+-ATPase Activity during Growth and Development of Juvenile Daubed Shanny Leptoclinus maculatus (Fries, 1838) in the Arctic

The dynamics of cortisol level and Na+/K+-ATPase activity that are associated with the maintenance of cell ion homeostasis was studied in skeletal muscles of juvenile circumpolar fish daubed shanny Leptoclinus maculatus (Fries, 1838), an ecologically significant representative of the ichthyofauna of the Arctic Svalbard Archipelago. It was established that the level of cortisol and Na+/K+-ATPase activity decrease during the development of daubed shanny juveniles from stage L2 pelagic juveniles to stage L5 juveniles, which are mainly demersal. The results obtained suggest that cortisol may be involved in the regulation of the activity of one of the main osmoregulatory factors, Na+/K+-ATPase. This may be important for the growth and adaptation of pelagic juveniles of daubed shanny to the demersal habitat during postembryonic development in the Arctic.

Stratigraphic and Spatial Extent of HALIP Magmatism in Central Spitsbergen

AbstractRapid extensive magmatism may have a profound effect on global climate by liberating and releasing greenhouse gases to the atmosphere through contact metamorphism of lithologically heterogeneous host rocks and degassing of magma and associated lava flows. The high Arctic Archipelago of Svalbard offers accessible, superbly exposed outcrops revealing Early Cretaceous magmatism associated with the High Arctic Large Igneous Province (HALIP). In this contribution, we investigate the onshore‐offshore intrusive complex of central Spitsbergen formed due to HALIP activity, that is, the Diabasodden Suite. This is the most “data‐rich” part of Svalbard due to past petroleum exploration and research drilling. In this area, the predominantly dolerite intrusions are emplaced in a range of host rocks ranging from Permian carbonate‐dominated successions to organic‐rich shale‐dominated successions of Middle Triassic and Late Jurassic‐Early Cretaceous age. Two hundred sixty five individual igneous intrusions, covering 72 km2, are exposed onshore in the study area. This equates to approximately 0.14–2.5 km3 of emplaced magma. In addition, subsurface characterization using borehole, seismic and magnetic data indicates that an area of additional ca. 3,000 km2 is affected by magmatism (magma volume 3.2–195.2 km3). Wireline logs in boreholes characterize both intrusions and associated aureoles. Aureoles with very low resistivity indicate occurrence of organic‐rich shales suggesting past fluid circulation and de‐gassing. This study forms the foundation for quantifying HALIP‐related magmatism in the data‐poorer parts of Svalbard, and other circum‐Arctic basins.

Accelerated Glacier Mass Loss over Svalbard Derived from ICESat-2 in 2019–2021

The glaciers in Arctic Archipelago of Svalbard, located in the hotspot of global warming, are sensitive to climate change. The assessment of glacier mass balance in Svalbard is one of the hotspots in Arctic research. In this study, we use the laser altimetry ICESat-2 data to investigate the elevation and mass change of Svalbard from 2019 to 2021 by a hypsometric approach. It is shown that the Svalbard-wide elevation change rate is −0.775 ± 0.225 m yr−1 in 2019–2021, corresponding to the mass change of −14.843 ± 4.024 Gt yr−1. All regions exhibit a negative mass balance, and the highest mass loss rates are observed at Northwestern Spitsbergen. Compared with ICESat/ICESat-2 (2003–2008 to 2019) and Cryosat-2 (2011–2017) periods, the elevation change from 2019 to 2021 has accelerated, with an increase by 158.3% and 31.5%, respectively, leading to equilibrium line altitude increasing to 750 m. Among the seven subregions, four are accelerated. It is shown that the overall accelerated glacier mass loss in Svalbard is expected to be caused by increasing surge events and temperature rise.

RABIES IN ARCTIC FOX (VULPES LAGOPUS) AND REINDEER (RANGIFER TARANDUS PLATYRHYNCHUS) DURING AN OUTBREAK ON SVALBARD, NORWAY, 2011–12

Rabies is an important zoonotic disease with high fatality rates in animals and humans. In the Arctic, the Arctic fox (Vulpes lagopus) is regarded as the principal reservoir, but there is considerable debate about how the disease persists at the low population densities that are typical for this species. We describe an outbreak of rabies among Arctic foxes and Svalbard reindeer (Rangifer tarandus platyrhynchus) during 2011-12 on the remote Arctic archipelago of Svalbard, an area with a very low and relatively stable Arctic fox density. The aim of the research was to increase knowledge of Arctic rabies in this ecosystem and in the presumed spillover host, the Svalbard reindeer. Phylogenetic analysis of rabies virus (RABV) RNA isolates from Arctic fox and reindeer was performed, and clinical observations and histologic and immunohistochemical findings in reindeer were described. An ongoing capture-mark-recapture project allowed collection of serum samples from clinically healthy reindeer from the affected population for detection of rabies virus-neutralizing antibodies. The outbreak was caused by at least two different variants belonging to the RABV Arctic-2 and Arctic-3 clades, which suggests that rabies was introduced to Svalbard on at least two different occasions. The RABV variants found in Arctic fox and reindeer were similar within locations, suggesting that Arctic foxes and reindeer acquired the infection from the same source(s). The histopathologic and immunohistochemical findings in 10 reindeer were consistent with descriptions in other species infected with RABV of non-Arctic lineages. Evidence of RABV was detected in both brain and salivary gland samples. None of 158 examined serum samples from clinically healthy reindeer had virus-neutralizing antibodies against RABV.

Parasite–copepod interactions in Svalbard: diversity, host specificity, and seasonal patterns

Copepods of the genera Calanus and Pseudocalanus are important components of Arctic marine ecosystems. Despite the key roles of these zooplankters, little is known about the organisms they interact with most intimately, their parasites and symbionts. We applied metabarcode sequencing to uncover eukaryotic parasites present within these two copepod genera from three areas around the high Arctic archipelago of Svalbard. Ten distinct parasite groups were observed: four different Apostome ciliates, four different dinoflagellates (Chytriodinium sp., Ellobiopsis sp., Thalassomyces sp., and Hematodinium sp.), a Paradinium sp., and a trematode. Apostome ciliates closely related to Pseudocollinia spp. were the most commonly observed parasite, with overall infection rates of 21.5% in Calanus and 12.5% in Pseudocalanus. Infection by these ciliates varied seasonally, with no infections observed in early winter, but infection rates exceeding 75% in spring. Host specificity varied between parasites, with significant differences in infection rate between the two host copepod genera for four parasites (two ciliates, Chytriodinium, and a trematode). The diverse assemblage of parasites observed in these copepods, and the frequency of infection, with over one in five copepod individuals infected, suggest parasites may be playing a greater role in Arctic plankton communities than generally acknowledged.

Emission of nanoparticles from coal and diesel fired power plants on Svalbard: An electron microscopy study

Sub-micrometer aerosol particles were collected at the stack of two coal power plants (Barentsburg, Longyearbyen), two diesel power plants (Pyramiden, Sveagruva) and one small-scale coal-burning boiler (Pyramiden) on the Arctic archipelago of Svalbard (Norway). Primary particles (n = 5752) in the size range of 100–1000 nm were investigated by operator-controlled high-resolution scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDX). Based on morphology and chemical composition primary particles were assigned to one of the following groups: soot, carbonaceous, fly ash spheres, Hg-containing particles, and mineral particles. Soot is the dominating particle group in most samples with a relative number abundance between 69 and 98%. Two coal burning samples have significantly lower soot contents of about 12 and 31%. The relative number abundance of the other particle groups is highly variable.The chemical composition of soot, fly ash spheres and mineral particles was studied in more detail. Soot particles from coal burning are significantly enriched in the elements S, Na, and K compared to diesel soot. The P contents of soot, fly ash spheres, and mineral particles reflect the variable concentration of this element in the different coal seams. Fly ash spheres from coal burning consist of a Si-rich component (quartz or silica glass), alumosilicates or alumosilicate glass, Fe oxides and a Fe, Ca, Al component (most likely a mechanical mixture of spinel and gypsum or lime). Fly ash spheres from diesel burning have a similar composition except that the Fe, Ca, Al component does not occur. Mineral particles from coal burning may be divided into Si-rich (quartz or silica glass), Pb-rich, Fe oxides, alumosilicates or alumosilicate glass and Na-rich particles (most likely a mechanical mixture of Si-rich particles with aged sea salt). The relative number abundance of these subgroups of mineral particles is highly variable. Mineral particles are rare in diesel burning, and seem to be mostly Fe oxides.The observed differences in minor element contents can be used in source apportionment studies for discrimination of individual soot particles as well as fly ash spheres from coal and diesel burning. The highly variable abundance of soot and of mineral particles (especially those consisting predominantly of toxic metals as for example Pb) should be taken into account in exposure assessment.

Ichnodiversity in the eastern Canadian Arctic in the context of polar microbioerosion patterns

Studies of marine microbioerosion in polar environments are scarce. They include our recent investigations of bioerosion traces preserved in sessile balanid skeletons from the Arctic Svalbard archipelago and the Antarctic Ross Sea. Here, we present results from a third study site, Frobisher Bay, in the eastern Canadian Arctic, together with a synthesis of our current knowledge of polar bioerosion in both hemispheres. Barnacles from 62 to 94 m water depth in Frobisher Bay were prepared using the cast-embedding technique to enable visualization of microboring traces by scanning electron microscopy. In total, six ichnotaxa of traces produced by organotrophic bioeroders were found. All recorded ichnotaxa were also present in Mosselbukta, Svalbard, and most in the Ross Sea. Frobisher Bay contrasts with Mosselbukta in that it is a siliciclastic-dominated environment and shows a lower ichnodiversity, which may be accounted for by the limited bathymetrical range and a high turbidity and sedimentation rate. We evaluate potential key ichnotaxa for the cold-temperate and polar regions, of which the most suitable are Flagrichnus baiulus and Saccomorpha guttulata, and propose adapted index ichnocoenoses for the interpretation of palaeobathymetry accordingly. Together, the three studies allow us to make provisional considerations about the biogeographical distribution of polar microbioerosion traces reflecting the ecophysiological limits of their makers.

Enhancing seismic calving event identification in Svalbard through empirical matched field processing and machine learning

SUMMARY Seismic signals generated by iceberg calving can be used to monitor ice loss at tidewater glaciers with high temporal resolution and independent of visibility. We combine the empirical matched field (EMF) method and machine learning using convolutional neural networks (CNNs) for calving event detection at the Spitsbergen (SPITS) seismic array and the single broad-band station KBS on the Arctic Archipelago of Svalbard. EMF detection with seismic arrays seeks to identify all signals generated by events in a confined target region similar to single P and/or S phase templates by assessing the beam power obtained using empirical phase delays between the array stations. The false detection rate depends on threshold settings and therefore needs appropriate tuning or, alternatively, post-processing. We combine the EMF detector at the SPITS array, as well as an STA/LTA (short term average/long term average) detector at the KBS station, with a post-detection classification step using CNNs. The CNN classifier uses waveforms of the three-component record at KBS as input. We apply the methodology to detect and classify calving events at tidewater glaciers close to the KBS station in the Kongsfjord region in Northwestern Svalbard. In a previous study, a simpler method was implemented to find these calving events in KBS data, and we use it as the baseline in our attempt to improve the detection and classification performance. The CNN classifier is trained using classes of confirmed calving signals from four different glaciers in the Kongsfjord region, seismic noise examples and regional tectonic seismic events. Subsequently, we process continuous data of six months in 2016. We test different CNN architectures and data augmentations to deal with the limited training data set available. Targeting Kronebreen, one of the most active glaciers in the Kongsfjord region, we show that the best performing models significantly improve the baseline classifier. This result is achieved for both the STA/LTA detection at KBS followed by CNN classification, as well as EMF detection at SPITS combined with a CNN classifier at KBS, despite of SPITS being located at 100 km distance from the target glacier in contrast to KBS at 15 km distance. Our results will further increase confidence in estimates of ice loss at Kronebreen derived from seismic observations which in turn can help to better understand the impact of climate change in Svalbard.

Historical glacier change on Svalbard predicts doubling of mass loss by 2100.

The melting of glaciers and ice caps accounts for about one-third of current sea-level rise1-3, exceeding the mass loss from the more voluminous Greenland or Antarctic Ice Sheets3,4. The Arctic archipelago of Svalbard, which hosts spatial climate gradients that are larger than the expected temporal climate shifts over the next century5,6, is a natural laboratory to constrain the climate sensitivity of glaciers and predict their response to future warming. Here we link historical and modern glacier observations to predict that twenty-first century glacier thinning rates will more than double those from 1936 to 2010. Making use of an archive of historical aerial imagery7 from 1936 and 1938, we use structure-from-motion photogrammetry to reconstruct the three-dimensional geometry of 1,594 glaciers across Svalbard. We compare these reconstructions to modern ice elevation data to derive the spatial pattern of mass balance over a more than 70-year timespan, enabling us to see through the noise of annual and decadal variability to quantify how variables such as temperature and precipitation control ice loss. We find a robust temperature dependence of melt rates, whereby a 1 °C rise in mean summer temperature corresponds to a decrease in area-normalized mass balance of -0.28 m yr-1 of water equivalent. Finally, we design a space-for-time substitution8 to combine our historical glacier observations with climate projections and make first-order predictions of twenty-first century glacier change across Svalbard.

'Ten Years After'-a long-term settlement and bioerosion experiment in an Arctic rhodolith bed (Mosselbukta, Svalbard).

Rhodolith beds and bioherms formed by ecosystem engineering crustose coralline algae support the northernmost centres of carbonate production, referred to as polar cold-water carbonate factories. Yet, little is known about biodiversity and recruitment of these hard-bottom communities or the bioeroders degrading them, and there is a demand for carbonate budgets to include respective rates of polar carbonate build-up and bioerosion. To address these issues, a 10-year settlement and bioerosion experiment was carried out at the Arctic Svalbard archipelago in and downslope of a rhodolith bed. The calcifiers recorded on experimental settlement tiles (56 taxa) were dominated by bryozoans, serpulids and foraminiferans. The majority of the bioerosion traces (30 ichnotaxa) were microborings, followed by attachment etchings and grazing traces. Biodiversity metrics show that calcifier diversity and bioerosion ichnodiversity are both elevated in the rhodolith bed, if compared to adjacent aphotic waters, but these differences are statistically insignificant. Accordingly, there were only low to moderate dissimilarities in the calcifier community structure and bioerosion trace assemblages between the two depth stations (46 and 127m), substrate orientations (up- and down-facing) and substrate types (PVC and limestone), in that order of relevance. In contrast, surface coverage as well as the carbonate accretion and bioerosion rates were all significantly elevated in the rhodolith bed, reflecting higher abundance or size of calcifiers and bioerosion traces. All three measures were highest for up-facing substrates at 46m, with a mean coverage of 78.2% (on PVC substrates), a mean accretion rate of 24.6gm-2 year-1 (PVC), and a mean bioerosion rate of -35.1gm-2 year-1 (limestone). Differences in these metrics depend on the same order of factors than the community structure. Considering all limestone substrates of the two platforms, carbonate accretion and bioerosion were nearly in balance at a net rate of -2.5gm-2 year-1 . A latitudinal comparison with previous settlement studies in the North Atlantic suggests that despite the harsh polar environment there is neither a depletion in the diversity of hard-bottom calcifier communities nor in the ichnodiversity of grazing traces, attachment etchings and microborings formed by organotrophs. In contrast, microborings produced by phototrophs are strongly depleted because of limitations in the availability of light (condensed photic zonation, polar night, shading by sea ice). Also, macroborings were almost absent, surprisingly. With respect to carbonate production, the Svalbard carbonate factory marks the low end of a latitudinal gradient while bioerosion rates are similar or even higher than at comparable depth or photic regime at lower latitudes, although this might not apply to shallow euphotic waters (not covered in our experiment), given the observed depletion in bioeroding microphytes and macroborers. While echinoid grazing is particularly relevant for the bioerosion in the rhodolith bed, respective rates are far lower than those reported from tropical shallow-water coral reefs. The slow pace of carbonate production but relatively high rates of bioerosion (both promoted by low carbonate supersaturation states in Arctic waters), in concert with high retention of skeletal carbonates on the seafloor and no calcite cements forming in open pore space created by microborers, suggest a low fossilisation potential for polar carbonates, such as those formed in the Mosselbukta rhodolith beds.