Northern Svalbard Research Articles

Lipid and fatty acid turnover of the pteropods Limacina helicina, L. retroversa and Clione limacina from Svalbard waters

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 609:133-149 (2019) - DOI: https://doi.org/10.3354/meps12837 Lipid and fatty acid turnover of the pteropods Limacina helicina, L. retroversa and Clione limacina from Svalbard waters Lauris Boissonnot1,2,*, Barbara Niehoff1, Benedikt Ehrenfels2,3, Janne E. Søreide2, Wilhelm Hagen4, Martin Graeve1 1Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany 2University Centre in Svalbard, 9171 Longyearbyen, Norway 3University of Bayreuth, Universitätsstrasse 30, 95447 Bayreuth, Germany 4BreMarE Bremen Marine Ecology, Marine Zoology, University of Bremen, 28334 Bremen, Germany *Corresponding author: lauris.boissonnot@gmail.com ABSTRACT: This study aimed at a better understanding of the fatty acid (FA) turnover in Arctic pteropods. Thecosome pteropods, i.e. Limacina helicina (juveniles and adults) and L. retroversa (adults), were collected in summer/autumn in Kongsfjorden and Isfjorden (Svalbard, 78° N) and, for the first time, successfully fed with 13C-labeled algae for 6 d. The gymnosome pteropod Clione limacina was sampled in summer in northern Svalbard and fed with 13C-labeled L. retroversa for 23 d. FA compositions were determined by gas chromatography, and 13C enrichment of FAs was analyzed by compound-specific isotope analysis. Among the thecosomes, maximum lipid turnover occurred in L. retroversa adults (1.3% d-1). L. helicina adults and juveniles showed lower lipid turnover rates (0.1 and 0.2% d-1, respectively). The thecosomes exhibited the ability to assimilate omega-3 FAs (up to 8.0% d-1). The lipid turnover rate of C. limacina averaged at only 0.07% d-1. However, C. limacina clearly showed the unusual capacity of de novo synthesis of odd-chain FAs (up to 1.2% d-1). Lipid turnover rates of pteropods were lower than those reported for Arctic copepods. However, pteropods may play a substantial role in the transfer of lipids to higher trophic levels, especially in autumn, when copepods have descended from the upper layers of the water column. The pteropods also showed the capacity to channel particular compounds such as omega-3 and odd-chain FAs, and therefore could be important for the functional diversity of the Arctic zooplankton community. KEY WORDS: Fatty acid assimilation · Trophic transfer · Omega-3 fatty acids · 13C labeling · Compound-specific isotope analysis · CSIA · Arctic Full text in pdf format PreviousNextCite this article as: Boissonnot L, Niehoff B, Ehrenfels B, Søreide JE, Hagen W, Graeve M (2019) Lipid and fatty acid turnover of the pteropods Limacina helicina, L. retroversa and Clione limacina from Svalbard waters. Mar Ecol Prog Ser 609:133-149. https://doi.org/10.3354/meps12837 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 609. Online publication date: January 17, 2019 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2019 Inter-Research.

A 190-ka biomarker record revealing interactions between sea ice, Atlantic Water inflow and ice sheet activity in eastern Fram Strait

The northeastern Fram Strait at the entrance to the Arctic Ocean represents a key observatory for sea ice reconstructions as it sensitively reacts to environmental changes. A combined biomarker approach (HBIs, sterols, alkenones) was carried out on Core PS93/006-1 from the western Svalbard margin to reconstruct sea ice conditions related to glacial–interglacial cycles of the last 190 ka. The continuous presence of sea ice demonstrates the strong influence of polar water masses in the eastern Fram Strait. Glacial intervals are characterised by extended sea ice conditions with perennial sea ice cover during early MIS 6, the Penultimate Glacial Maximum, the interstadial MIS 5d, MIS 4 and the Last Glacial Maximum. Less severe, yet highly variable, sea ice conditions with more frequent summer melt dominated the interglacial stages. The opposing sea ice conditions along the western and northern Svalbard margin highlight the different regional impact of various environmental forces in eastern Fram Strait. Thus, the major expansion of the Svalbard Barents Sea Ice Sheet favoured the formation of perennial sea ice west of Svalbard while it triggered the establishment of marginal ice cover on the Yermak Plateau.

Comment on “The Keisarhjelmen detachment records Silurian–Devonian extensional collapse in Northern Svalbard”

This is the peer reviewed version of the following article: Dallmann, W. & Piepjohn, K. (2018). Comment on “The Keisarhjelmen detachment records Silurian–Devonian extensional collapse in Northern Svalbard”. Terra Nova. 30(4), 319-321, which has been published in final form at https://doi.org/10.1111/ter.12335 . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.

Reply to Comment on “The Keisarhjelmen detachment records Silurian–Devonian extensional collapse in Northern Svalbard”

Reply to Comment on “The Keisarhjelmen detachment records Silurian–Devonian extensional collapse in Northern Svalbard”

Late Weichselian ice stream configuration and dynamics in Albertini Trough, northern Svalbard margin

Ice stream configuration and sedimentary processes in Albertini Trough, north of Nordaustlandet, were studied using multibeam bathymetry, seismic reflection and sub-bottom profiles together with sediment gravity cores. Progradational sediment packages in the outer Albertini Trough suggest that streaming ice reached the shelf edge multiple times during the last c. 2.6 Ma. S–N-oriented glacial lineations imply that the Last Glacial Maximum (LGM) ice flow reached Albertini Trough mouth, and likely sourced from Duvefjorden and Albertinibukta. The ice flows from these two areas were separated on the inner shelf until they merged north of Karl XII Island, suggesting a geologic control on the ice flows. The scarceness of landforms characteristic of grounded ice margin retreat in the outermost Albertini Trough suggests a locally floating ice tongue. The presence of iceberg ploughmarks on the outer shelf suggests that the ice margin mainly disintegrated through calving. Push moraines and De Geer moraines superimposed on terminal moraines and a grounding zone wedge with superimposed SSW–NNE-oriented glacial lineations indicate a stepwise retreat of the ice margin with at least three readvances during deglaciation. Grounding line stabilization in the outer Albertini Trough is partly attributed to southwards shallowing and narrowing trough geometry. However, a southwards change in the orientation of glacial lineations from S–N to SSW–NNE suggests that the ice flow from Duvefjorden became more dominant in Albertini Trough during deglaciation. Spacing between the De Geer moraines generally increases southwards in Albertini Trough, implying an increased retreat rate during deglaciation. Three acoustic units were distinguished in the chirp data and correlated with till, glacimarine and marine deposits, respectively. Two sediment cores west of Albertini Trough consist of subglacial diamicton at the base with a sharp transition to homogenous marine mud above. The diamicton–mud transition in the cores was 14C-dated to 15.3 and 14.0 ka, implying increased retreat rate of the ice sheet margin during deglaciation across the continental shelf. The increased retreat rate is attributed to rapid sea level rise. Well-preserved listric fault scarps in the Albertini Trough mouth indicate relatively recent formation. The locally downfaulted bedrock beneath the glacial–interglacial sediments at the trough mouth probably contributed to the formation of thick and unstable sediment succession, which resulted in the faulting.

Temperature (latitude) and nutrient (seabird guano) effects on limno-terrestrial Tardigrada (Testechiniscus spitsbergensisandPilatobius recamieri) body size

ABSTRACTSurveys of terrestrial microinvertebrate morphometry, especially spatial patterns of body size at wider geographical scales, including the polar regions, are very scarce. In this study, we focused on Tardigrada, common limno-terrestrial microinvertebrates. Considering Bergmann’s rule, originally formulated for endothermic animals, we tested the hypothesis that body length of limno-terrestrial tardigrades augments with increasing latitude and decreasing temperature. Since some of our sampling areas adjoined seabird colonies, we also explored the effects of nutrients from seabird guano deposits. Individual body length of Testechiniscus spitsbergensis was measured in populations obtained from seven localities distributed along a latitudinal gradient extending from 45°N (northern Italy) to 79°N (northern Svalbard), and for Pilatobius recamieri from three localities in Svalbard (77°N-80°N). Considering both latitude and proximity to a seabird colony there were significant effects of locality on the bod...

Radionuclide activities in sediments on the northern coast of Spitsbergen

AbstractThe specific activity of natural gamma emitters like actinium (228Ac), bismuth (212Bi,214Bi), lead (212Pb,214Pb), potassium (40K), radium (224Ra), thallium (208Tl) and artificial radioisotope caesium (137Cs) was measured in 2005 in the surface layer of marine sediments in the northern Svalbard: Wijdefjorden, Woodfjorden, Vestfjorden and Bockfjorden as well as in the freshwater reservoirs in Andre Land. Nonuniform spatial distribution of these radionuclides was found. Sediment sample from Bockfjorden had the highest specific activities of all natural radionuclides. The specific radioactivity of137Cs was much lower than specific radioactivities of natural radionuclides but there were differences between investigated locations. The distribution of137Cs is similar to persistent organic pollutants of the lake sediments in the area.

Submarine glacial landforms and sedimentary environments in Vaigattbogen, northeastern Spitsbergen

Vaigattbogen is located in northern Svalbard. The area is currently affected by several tidewater glaciers. This study uses multibeam-, sub-bottom acoustic data, and four sediment cores to reconstruct the Late Weichselian and Holocene glacial history in Vaigattbogen. During the last glacial, ice flowed northwards through Vaigattbogen and fed into the Hinlopen Strait Ice Stream. Streamlined bedforms indicate relatively fast ice flow and their increasing elongation ratios towards the north suggest increasing flow velocities. De Geer moraines in the shallower parts of Vaigattbogen imply that multiple halts and/or re-advances interrupted the ice retreat in these areas. A sediment core suggests that the north basin deglaciated prior to 9.1cal.kaBP. In the south basin, two large moraine ridges and networks of crevasse-squeeze ridges suggest that at least two surge-type advances occurred during the Holocene. The Hinlopenbreen glacier surged in the early 1970s and deposited the inner (R.2) of the two large moraine ridges. Radiocarbon ages from a sediment core recovered from the crest of the outer (R.1) ridge yield a basal age of 2.6cal.kaBP. However, the core did not sample subglacial diamict and the age of the ridge could be anything between 2.6cal.kaBP and early Holocene. The R.1 ridge formed prior to the Little Ice Age (LIA), implying that more than one tidewater glacier has experienced a pre-LIA surge on the east coast of Spitsbergen, suggesting that surging during the Holocene was a regional phenomenon. The R.1 ridge is double-crested with small crevasse-squeeze ridges between the crests suggesting that more than one surge-type advance occurred during the Holocene reaching approximately the same location. Data from eastern Svalbard indicate differences in surge-landform assemblages suggesting that different mechanisms could have governed surge-cycles throughout the Holocene.

The role of local and regional environmental factors for Calanus finmarchicus and C. hyperboreus abundances in the Nordic Seas

In the advective realm of the seas, it is challenging to disentangle the role of regional and local processes on zooplankton populations. However, comparative studies of spatially separated zooplankton populations can provide valuable insights into this issue. We studied interannual abundance variation of the key zooplankton species Calanus finmarchicus and C. hyperboreus in three near-shore locations of the Nordic Seas: off northern Norway, Svalbard, and northern Iceland. Average abundances of both species were similar among locations, while in each location the abundance of C. finmarchicus was about an order of magnitude higher than the abundance of C. hyperboreus. The abundance of both species decreased in northern Norway, while C. finmarchicus abundance increased in northern Iceland. C. finmarchicus abundance in northern Norway covaried with regional climate, while the Svalbard Calanus populations were related to local environment (hydrography, phytoplankton). In northern Iceland, C. finmarchicus abundance covaried with local environmental factors, while C. hyperboreus abundance covaried with climate variability. Top-down forcing could not be investigated. The results indicate that the mechanisms relating regional climate variability (North Atlantic and Arctic oscillations) to Calanus abundance are mediated through advection of water masses, while more local environmental variability involved bottom-up processes or advection.

Past ice flow in Wahlenbergfjorden and its implications for late Quaternary ice sheet dynamics in northeastern Svalbard

Wahlenbergfjorden is a fjord situated in the western part of Nordaustlandet in northern Svalbard. It leads into the 400 m deep Hinlopen Strait located between Nordaustlandet and Spitsbergen. High-resolution multibeam bathymetric and sub-bottom data, as well as sediment cores are used to study the past extent and dynamics of glaciers in Wahlenbergfjorden and western Nordaustlandet. The submarine landform assemblage in Wahlenbergfjorden consists of landforms characteristic of subglacial, ice marginal and proglacial conditions. Glacial lineations indicate that Wahlenbergfjorden was occupied by streaming ice during the LGM and most likely acted as an ice stream onset zone. Westward ice flow in the fjord merged with the ice stream in Hinlopen Strait. Absence of ice recessional landforms in outer Wahlenbergfjorden suggests relatively fast deglaciation, possibly by flotation of the glacier front in the deeper parts of the fjord. The inner part of Wahlenbergfjorden and Palanderbukta are characterized by De Geer moraines, indicating episodic retreat of a grounded glacier front. In Palanderbukta, longer still stands of the glacier terminus resulted in the formation of larger terminal moraine ridges. The inner part of Wahlenbergfjorden was deglaciated prior to 11.3 ± 55 Cal. ka BP. The submarine landform assemblages in front of Bodleybreen, Etonbreen, Idunbreen, Frazerbreen and Aldousbreen confirm that these glaciers have surged at least once during the Holocene.

Benthic foraminiferal biogeography in NW European fjords: A baseline for assessing future change

The seaboard extending from northern Svalbard to Scotland is the only region of the world where fjords have been comprehensively studied for their live (stained) benthic foraminiferal faunas. These modern faunas provide essential baseline data for the interpretation of the postglacial and continuing environmental changes in those fjords and this is the first biogeographic synthesis. The data come from the surface sediment assemblages (mainly sampled in the 1990's) from all the available literature. Due to limited information of shallow water assemblages in the north, only the species occurrences in deeper water from below the halocline are considered. Amongst these, only “common species” species occurring in more than one fjord are included. There is a clear pattern of distribution with five groups of taxa: 5 widespread species found throughout the region; 53 species reaching their northern limit; 13 species reaching their southern limit; 11 deep-sea species; 1 recently introduced species. Although there is an abrupt change in temperature from Tanafjorden in northern Norway to Hornsund in southern Svalbard, the faunal change from N to S is progressive throughout the investigated region. The area of overlap of the northern and southern species corresponds with the previously recognised boundary between the Barents Sea Province and the Norwegian Coast Province based on shelf and upper slope invertebrate macrofaunal benthos and plankton. Temperature is the main abiotic control on the distributions. For the fjords which have shallow sills separating them from the open shelf it is likely that most of the foraminiferal colonisers of the deeper fjord basins are sourced from the shelf or slope via propagules. One species has recently been introduced from further south into the southern region probably through the discharge of ballast water from ships. The biodiversity of the pristine Svalbard fjords extends below what is considered to reflect acceptable ecological status for mainland Norway, illustrating the need to introduce new methods to determine possible deviations from the reference conditions as defined in the EU's Water Framework Directive (WFD; 2000/60/EC). Altogether 347 species have so far been recorded in Norwegian waters: 214 in fjords (60 above and 180 below the halocline of which 26 occur both above and below the halocline) and 266 on the shelf and slope (133 of which also occur in fjords).

Geomorphology of the huge Hinlopen–Yermak landslide on the northern Svalbard margin

Submarine landslide scars, including the huge Hinlopen–Yermak slide-scar north of Svalbard (Fig. 1) (Vanneste et al. 2006; Winkelmann et al. 2006), are relatively common geomorphological features on glaciated continental margins. However, landslide characteristics, for example scar area, run-out and displaced volume, vary significantly (Hogan et al. 2013). A key pre-condition for failure is rapid deposition of mainly diamictic glacier-derived sediment on the slope during full-glacials, alternating with fine-grained interglacial deposition. This layered architecture, and the varying geotechnical properties of the debris, facilitate downslope mass-movements with a variety of possible triggers. Fig. 1. Marine geophysical data over Hinlopen–Yermak landslide scar, northern Svalbard. ( a ) Multibeam image showing slide scar. PR, arcuate pressure ridges. DR, detached sediment ridges. Acquisition systems Kongsberg EM300. Frequency 30 kHz (RV Jan Mayen ). Hydrosweep DS2. Frequency 15.5 kHz (RV Polarstern ). Kongsberg EM120. Frequency 12 kHz (RSS James Clark Ross ). Grid-cell size 100 m. ( b ) Seismic-reflection profile of slide headwall and post-slide sediment fill. Acquisition system two 40 cubic inch airguns. VE×6. ( c ) Bathymetric image of the complex eastern headwall area showing detached sediment ridges (DR and inset; VE×7) and blocky debris (BD) on slip planes. ( d ) Bathymetric image of rafted mega-blocks within slide debris. Ridges of material pushed up …

Huge iceberg ploughmarks and associated corrugation ridges on the northern Svalbard shelf

Linear to curvilinear depressions on high-latitude continental shelves have long been regarded as the signature of the ploughing action of iceberg keels impinging on the sedimentary seafloor (e.g. Woodworth-Lynas et al. 1991). These depressions vary in dimensions and pattern with the size of calved icebergs and their drift tracks through the polar seas. Two different sizes of iceberg have affected the shelf north of Svalbard, producing distinctive sets of ploughmarks (Dowdeswell et al. 2010). Large numbers of linear and curvilinear depressions are present on the seafloor of the northern Svalbard margin at water depths of <615 m (Fig. 1). The depressions are of two types. The first are large quasi-linear features up to 23 km long, 1 km wide and 80 m deep (Fig. 1a, d). These features are clustered within a fairly well-defined band of water depths (from 400 to 615 m over an area of c. 800 km2), above and below which few are present. At first sight many features appear linear; detailed inspection shows that some are slightly curvilinear, whereas others are composed of several straight sections interspersed with directional shifts of sometimes just a few degrees. In addition, individual linear features often appear to …

Glaciomarine sedimentation and bottom current activity on the north-western and northern continental margins of Svalbard during the late Quaternary

Palaeo-bottom current strength of the West Spitsbergen Current (WSC) and the influence of the Svalbard-Barents Sea Ice Sheet (SBIS) on the depositional environment along the northern Svalbard margins are poorly known. Two gravity cores from the southern Yermak Plateau and the upper slope north of Nordaustlandet, covering marine isotope stage (MIS) 1 to MIS 5, are investigated. Five lithofacies, based on grain size distribution, silt/clay ratio, content and mean of sortable silt (SS), are distinguished to characterise the contourite-dominated sedimentary environments. In addition, depositional environments are described using total organic carbon (TOC), total sulphur (TS) and calcium carbonate (CaCO3) contents of sediments. Facies A, containing coarse SS, suggests strong bottom current activity and good bottom water ventilation conditions as inferred from low TOC content. This facies was deposited during the glacial periods MIS 4, MIS 2 and during the late Holocene. Facies B is dominated by fine SS indicating weak bottom current and poor ventilation (cf. high TOC content of 1.2–1.6%), and correlates with the MIS 4/3 and MIS 2/1 transition periods. With an equal amount of clay and sand, fine SS and high content of TOC, facies C indicates reduced bottom current strength for intervals with sediment supply from proximal sources such as icebergs, sea ice or meltwater discharge. This facies was deposited during the last glacial maximum. Facies D represents mass-flow deposits on the northern Svalbard margin attributed to the SBIS advance at or near the shelf edge. Facies E sediments indicating moderate bottom current strength were deposited during MIS 5 and MIS 3, and during parts of MIS 2. This first late Quaternary proxy record of the WSC flow and sedimentation history from the northern Svalbard margin suggests that the oceanographic conditions and ice sheet processes have exerted first-order control on sediment properties.

Morphology, distribution and biology of Mycobates sarekensis (Acari: Oribatida: Punctoribatidae)

Mycobates sarekensis (Trägårdh, 1910) is a typical component of the Svalbard archipelago, but its morphological ontogeny is unknown, and distribution and biology are known poorly. The juveniles of this species are similar to those of other species of Mycobates with known ontogeny, but differ by the length of seta c3 in all juvenile stages and the presence of a humeral organ and gastronotal shield in the larva. The nymphs of M. sarekensis have shorter seta c3 than those of Mycobates acuspidatus and Mycobates royi, whereas the larva of M. sarekensis has shorter seta c3 than that of M. acuspidatus and has a humeral organ, which is absent in the latter species. The larva of M. royi differs from those of M. sarekensis and M. acuspidatus by presence of gastronotal shield, which is absent in other species. The adult of Mycobates tridactylus is similar to that of M. sarekensis and we provisionally consider it as a synonym of M. sarekensis. In Svalbard, this species achieved the highest density in swamp and wet moss tundra, and in most other plant classes was not abundant. In M. sarekensis, the males dominated the females, and in extracted samples the juveniles of M. sarekensis was not abundant or absent. The mean body length of females was greater than that of males, and the adults from the cold polar desert areas in northern Svalbard were usually smaller than those from the warmer and very nutrient-rich ornigenic soils on Storholmen.

Palaeoceanography of the Barents Sea continental margin, north of Nordaustlandet, Svalbard, during the last 74 ka

We investigated gravity core HH11‐09GC from 488 m water depth at the northern Svalbard margin in order to reconstruct changes in Atlantic Water (AW) inflow to the Arctic Ocean. The study was based on the distribution patterns of benthic and planktic foraminifera, benthic and planktic oxygen and carbon isotopes, lithology and physical properties of the sediments. The core contains sediments from Marine Isotope Stages (MISs) 5a to 1. MIS 4 was characterized by glacial conditions and at c. 65 ka the Svalbard‐Barents Sea Ice Sheet (SBIS) advanced. Polynya was formed in front of the SBIS at c. 62 ka. During late MIS 3 (32–29 ka) and MIS 2 (22–20 ka), a strong influence of AW resulted in high productivity of both planktic and benthic foraminiferal faunas. During 23–22 ka, the SBIS advanced to the shelf edge. The last deglaciation began at 18.5 ka and at 16.9 ka ‘a peak’ influx of meltwater from the retreating SBIS caused a weakening of the ocean circulation. At the start of the Bølling‐Allerød interstadial at c. 15.5 ka, inflow of relatively warm AW probably intensified the release of meltwater at 14 and 12.8 ka. This probably led to expansion of sea ice cover during the Younger Dryas stadial. The late Holocene from 3.7 ka was characterized by the presence of seasonal to perennial sea ice cover and a slight warming of the bottom waters. The sea ice cover decreased for a short period at 1.5 ka owing to the advection of relatively warm AW. Correlation with results from the northwestern Svalbard margin shows that the patterns of ice retreat and advance correlate closely with changes in inflow of AW and were regulated by meltwater discharge, sea ice export and insolation.

A review of the subspecies status of the Icelandic Purple Sandpiper Calidris maritima littoralis

The Icelandic Purple Sandpiper Calidris maritima littoralis (C.L. Brehm, 1831) represents one member of a poorly understood subspecies complex. Currently, differences in size define two other subspecies: Calidris maritima belcheri Engelmoer & Roselaar, 1998, which breeds in north-eastern Canada along the Hudson Bay and James Bay, and Calidris maritima maritima (Brunnich, 1764), which breeds along the Arctic coasts elsewhere in northern Canada, Greenland, Svalbard, Scotland, and Fennoscandia, to northern central Siberia. There are large size differences amongst populations of C. m. maritima, however. As an Arctic/Alpine breeding bird, C. m. littoralis could provide an interesting perspective on the evolutionary changes following a northwards expansion of a species after glacial retreat. Considering the extent of the ice sheet in the northern hemisphere during the last glaciation, and the short period of time since it ended, the correct attribution of subspecies status for C. m. maritima may reflect either rapid diversification from a single population or ancestral splits of distinct evolutionary lineages that survived in isolation at southern latitudes. We applied morphometric subspecies criteria, diagnosability by Amadon’s rule, and genetic analysis of five nuclear introns, and the mitochondrial DNA markers cytochrome oxidase c subunit I (COI) and NADH dehydrogenase subunit 2 (ND2), to geographically separate breeding populations in order to examine the subspecies status of the Icelandic population. The results do not provide support for the subspecies status of the Icelandic population because the nominate and Icelandic subspecies fail to uphold Amadon’s rule, and genetic analyses indicate that the study populations derive from a single shared refugium.

Distribution and composition of the epibenthic megafauna north of Svalbard (Arctic)

Benthic communities north of Svalbard are less investigated than in other Arctic shelf regions, as this area was covered by sea-ice during most of the year. Improving our knowledge on this region is timely, however, since climate change is strongly evident there, particularly with regard to the extent of sea-ice decline and its huge ecological impact on all marine biota, including the benthos. Moreover, longer ice-free periods will certainly lead to an increase in human activity levels in the area, including bottom trawling. In two adjacent shelf and slope regions off northern Svalbard, we studied the composition of epibenthic megafauna and seafloor habitat structures by analyzing seabed images taken with both still and video cameras. In addition, we also used an Agassiz trawl to catch epibenthic organisms for ground-truthing seabed-image information. A wide variety of mostly sessile organisms 141 epibenthic taxa were identified in the images. The brittle star Ophiura sarsii and the soft coral Gersemia rubiformis were the most common species. At all stations >300 m in depth, evidence of trawling activities was detected at the seabed. The distribution of the benthic fauna in the study area exhibited a clear depth zonation, mainly reflecting depth-related differences in seabed composition. We conclude that natural factors determining the composition of the seafloor mostly affect the distribution and composition of epibenthic assemblages. Anthropogenic impact indicated by the trawl scours found is likely also important at smaller spatial scales.

Polar bears (Ursus maritimus) mating during late June on the pack ice of northern Svalbard, Norway

Polar bears are seasonal breeders and typically mate from late March to early May. Implantation is, however, delayed until autumn, which can allow plasticity in the date of mating. As for other seasonal breeders, a rapid return to estrus after the loss of dependent offspring can be expected, even into the summer. A few earlier observations and dissections of dead animals suggest that polar bears are able to mate in summer. We report on a mating incident on 29 June 2014, the first documented mating this late in the season among wild polar bears. The female had lost her dependent cub during the period prior to the mating event. We speculate that she lost this cub late in the mating season, entered estrus and successfully mated in late June. Keywords: Polar bear; mating season; mating behaviour; Svalbard; Arctic. (Published: 2 March 2015) Citation: Polar Research 2015, 34 , 25786, http://dx.doi.org/10.3402/polar.v34.25786

Spatial distribution of air temperature on Svalbard during 1 year with campaign measurements

ABSTRACTIn this article, the results of an investigation into the air temperature conditions on Svalbard in the period 1 September 2010 to 31 August 2011 are presented. For this period, parallel temperature measurements have been made as many as in 30 sites. On the basis of this unique set of data it was possible to study, in detail, the spatial distribution of different thermal characteristics [mean temperature, diurnal temperature range (DTR), day‐to‐day variability, degree of climate continentality, etc.] in Svalbard. Such knowledge of the whole of Svalbard was not previously available with sufficient accuracy for all areas. High resolution maps showing the spatial distribution of all studied thermal characteristics were also produced and analysed.Analysis of surface temperature data shows that the markedly coldest area throughout the whole year was northern Svalbard, and in particular its eastern side (Nordaustlandet). On the other hand, the highest temperatures were recorded in western part of Spitsbergen. The greatest spatial decreasing rate of temperature in Svalbard throughout the whole year was observed in a southwest (SW)–northeast (NE) direction. The distribution of mean seasonal and annual temperature reduced to sea level on Svalbard differs from the distribution based on surface temperatures. Spring, and in particular winter, saw the greatest DTRs (4–7 and 6–9 °C, respectively), while the lowest were observed in summer (3.0–3.5 °C). In all seasons, the highest DTR were mainly noted in the NE part of Svalbard, while the lowest were in its SW part. The lowest continentality of climate (30%) is clearly seen in the south‐western part of Svalbard, while the highest values (above 43%) stretch from the western part of Nordaustlandet to the area of Sveagruva in the central‐eastern part of Spitsbergen. The NORA10 hindcast temperature data differ significantly from measured data for some seasons and areas and need bias corrections when used in climatology.