| 1. |
- Al-Handal, Adil Y, 1952, et al.
(författare)
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Observations on diatoms inhabiting natural and artificial substrates in Kongsfjorden, Svalbard, the Arctic
- 2016
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 39:11, s. 1913-1932
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Tidskriftsartikel (refereegranskat)abstract
- The most dramatic effects of global climate change are predicted for the Arctic, and there is a raising concern about the lack of baseline information on microalgal biodiversity. The present study was motivated by the general lack of information on species distribution of Arctic benthic diatoms and particularly studies providing photographs to facilitate morphological species identification. Diatoms were studied in samples collected from Ny lesund, Spitsbergen, Svalbard, during summer 2006 and spring 2008. Two types of samples were examined: diatoms scraped from ceramic tiles, immersed at 0.5 m depth (2006), and diatoms extracted from surface sediment, collected at 0.5 to 3 m depth (2008). A total number of 75 taxa belonging to 45 genera were encountered. Sixty-eight species were found in the sediment samples and 48 on the ceramic tiles, of which 41 species were found on both substrata. Common species of the tile assemblages were Fragilariopsis spp., Licmophora spp., Odontella aurita, Synedropsis hyperborea and Trachyneis aspera, while Thalassiosira spp., Diploneis spp. and Navicula spp. were common in the sediment samples. Twenty-five percent of the observed diatom species belonged to freshwater taxa brought to the fjord from surrounding meltwater and river discharges. ELMANN A, 1992, DEEP-SEA RESEARCH PART A-OCEANOGRAPHIC RESEARCH PAPERS, V39, PS525
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| 2. |
- Arcalis-planas, A., et al.
(författare)
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Limited use of sea ice by the Ross seal (Ommatophoca rossii), in Amundsen Sea, Antarctica, using telemetry and remote sensing data
- 2015
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 38:4, s. 445-461
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Tidskriftsartikel (refereegranskat)abstract
- To understand the use and importance of the Antarctic sea ice to the Ross seal (Ommatophoca rossii), four adult females were tagged with Argos satellite transmitters in the Amundsen Sea, Antarctica. The Ross seal is the least studied of the Antarctic seal species and nothing was previously known about their behaviour in the Amundsen Sea. During almost 1 year, their movements, haul out behaviour and time spent at different temperatures were logged. By comparing their movements with daily ice maps, distances to the ice edge were calculated, and seals dependence on sea ice for resting, breeding and moulting was analysed. The tagged seals spent on average 70.8 % (range 66.8–77.8 %) of their time in the water and hauled out mainly during the moult in December–January, and in late October–mid-November during breeding. During the pelagic period, they were on average 837.5 km (range 587–1,282 km) from the ice edge indicating a fully pelagic life during several months. Their pelagic behaviour suggests that Ross seals, although being an ice obligate species, may adapt comparatively easy to climate change involving ice melting and recession and thereby potentially being less sensitive to the reduction of sea ice than other Antarctic seal species. Although nothing is known about their mating behaviour, they appear to be relatively stationary during moulting and breeding, hence requiring a small ice surface. Although previous studies in other parts of Antarctica have found similar results, still many questions remain about this peculiar species.
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| 3. |
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| 4. |
- Barrio, Isabel C., et al.
(författare)
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Background invertebrate herbivory on dwarf birch (Betula glandulosa-nana complex) increases with temperature and precipitation across the tundra biome
- 2017
-
Ingår i: Polar Biology. - : Springer. - 0722-4060 .- 1432-2056. ; 40:11, s. 2265-2278
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Tidskriftsartikel (refereegranskat)abstract
- Chronic, low intensity herbivory by invertebrates, termed background herbivory, has been understudied in tundra, yet its impacts are likely to increase in a warmer Arctic. The magnitude of these changes is however hard to predict as we know little about the drivers of current levels of invertebrate herbivory in tundra. We assessed the intensity of invertebrate herbivory on a common tundra plant, the dwarf birch (Betula glandulosa-nana complex), and investigated its relationship to latitude and climate across the tundra biome. Leaf damage by defoliating, mining and gall-forming invertebrates was measured in samples collected from 192 sites at 56 locations. Our results indicate that invertebrate herbivory is nearly ubiquitous across the tundra biome but occurs at low intensity. On average, invertebrates damaged 11.2% of the leaves and removed 1.4% of total leaf area. The damage was mainly caused by external leaf feeders, and most damaged leaves were only slightly affected (12% leaf area lost). Foliar damage was consistently positively correlated with mid-summer (July) temperature and, to a lesser extent, precipitation in the year of data collection, irrespective of latitude. Our models predict that, on average, foliar losses to invertebrates on dwarf birch are likely to increase by 6-7% over the current levels with a 1 degrees C increase in summer temperatures. Our results show that invertebrate herbivory on dwarf birch is small in magnitude but given its prevalence and dependence on climatic variables, background invertebrate herbivory should be included in predictions of climate change impacts on tundra ecosystems.
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| 5. |
- Barrio, Isabel C., et al.
(författare)
-
Publisher Correction to : Background invertebrate herbivory on dwarf birch (Betula glandulosa-nana complex) increases with temperature and precipitation across the tundra biome (vol 40, pg 2265, 2017)
- 2018
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Ingår i: Polar Biology. - : Springer. - 0722-4060 .- 1432-2056. ; 41:8, s. 1653-1654
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Tidskriftsartikel (refereegranskat)abstract
- The above mentioned article was originally scheduled for publication in the special issue on Ecology of Tundra Arthropods with guest editors Toke T. Hoye . Lauren E. Culler. Erroneously, the article was published in Polar Biology, Volume 40, Issue 11, November, 2017. The publisher sincerely apologizes to the guest editors and the authors for the inconvenience caused.
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| 6. |
- Barthelemy, Hélène, et al.
(författare)
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Short- and long-term plant and microbial uptake of 15N-labelled urea in a mesic tundra heath, West Greenland
- 2024
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Ingår i: Polar Biology. - : Springer Nature. - 0722-4060 .- 1432-2056. ; 47:1, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- Terrestrial animals are key elements in the cycling of elements in the Arctic where nutrient availability is low. Waste production by herbivores, in particular urine deposition, has a crucial role for nitrogen (N) recycling, still, it remains largely unexplored. Also, experimental evidence is biased toward short-term studies and Arctic regions under high herbivore pressure. In this study, we aimed to examine the fate of N derived from urine in a nutrient poor tundra heath in West Greenland, with historical low level of herbivory. We performed a pulse labelling with 15N-urea over the plant canopy and explored ecosystem N partition and retention in the short-term (2 weeks and 1 year) and longer-term (5 years). We found that all vascular plants, irrespective of their traits, could rapidly take up N-urea, but mosses and lichens were even more efficient. Total 15N enrichment was severely reduced for all plants 5 years after tracer addition, with the exception of cryptogams, indicating that non-vascular plants constituted a long-term sink of 15N-urea. The 15N recovery was also high in the litter suggesting high N immobilization in this layer, potentially delaying the nutrients from urine entering the soil compartment. Long-term 15N recovery in soil microbial biomass was minimal, but as much as 30% of added 15N remained in the non-microbial fraction after 5 years. Our results demonstrate that tundra plants that have evolved under low herbivory pressure are well adapted to quickly take advantage of labile urea, with urine having only a transient effect on soil nutrient availability.
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| 7. |
- Becher, Marina, 1983-, et al.
(författare)
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Decreased cryogenic disturbance : one of the potential mechanisms behind the vegetation change in the Arctic
- 2018
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Ingår i: Polar Biology. - : Springer. - 0722-4060 .- 1432-2056. ; 41:1, s. 101-110
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- During the last few decades, the Arctic has experienced large-scale vegetation changes. Understanding the mechanisms behind this vegetation change is crucial for our ability to predict future changes. This study tested the hypothesis that decreased cryogenic disturbances cause vegetation change in patterned ground study fields (non-sorted circles) in Abisko, Sweden during the last few decades. The hypothesis was tested by surveying the composition of plant communities across a gradient in cryogenic disturbance and by reinvestigating plant communities previously surveyed in the 1980s to scrutinise how these communities changed in response to reduced cryogenic disturbance. Whereas the historical changes in species occurrence associated with decreased cryogenic disturbances were relatively consistent with the changes along the contemporary gradient of cryogenic disturbances, the species abundance revealed important transient changes highly dependent on the initial plant community composition. Our results suggest that altered cryogenic disturbances cause temporal changes in vegetation dynamics, but the net effects on vegetation communities depend on the composition of initial plant species.
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| 8. |
- Beyens, L., et al.
(författare)
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Are soil biota buffered against climatic extremes? An experimental test on testate amoebae in arctic tundra (Qeqertarsuaq, West Greenland)
- 2009
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 32, s. 453-462
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Tidskriftsartikel (refereegranskat)abstract
- Climate warming is likely to have pronounced impacts on soil biota in arctic ecosystems. In a warmer climate, heatwaves are more frequent and intense, but it is unclear to what extent soil communities are buffered against this. We studied the effects of an artificially induced heatwave on the structure of testate amoebae communities in dry heath tundra in Qeqertarsuaq (Disko Island, West Greenland) during the summer of 2003. While the heatwave was severe enough to induce significant leaf mortality in the aboveground vegetation, overall testate amoebae abundance did not react to the difference in temperature. However, in the heated plots transient shifts in species populations occurred during the exposure, followed by increases in species richness weeks after the heatwave had ended. The most important taxa appearing after the heating period belonged to bacterivorous genera, in agreement with a transient peak in bacterial colony forming units, caused by the heatwave. Lobose testate amoebae resisted the heating and its associated desiccation better than their filose counterparts.
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| 9. |
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| 10. |
- Bonnedahl, Jonas, 1970-, et al.
(författare)
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Antibiotic susceptibility of faecal bacteria in Antarctic penguins
- 2008
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Ingår i: Polar Biology. - : Springer. - 0722-4060 .- 1432-2056. ; 31:6, s. 759-763
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Tidskriftsartikel (refereegranskat)abstract
- Faecal bacteria from 49 Gentoo penguins on the Antarctic Peninsula were identified by biochemical methods and sequencing, and tested for antibiotic susceptibility using agar dilution. Of the 42 Enterobacteriaceae isolates found, 39 belonged to the genus Edwardsiella. All isolates were susceptible to the 17 antibiotics tested. This implies that antibiotic selection pressure is a prerequisite to a high prevalence of antibiotic resistance, and in the absence of contact with human activities, antibiotic resistance in Enterobacteriaceae remains undetectable.
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| 11. |
- Brutemark, A, et al.
(författare)
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An experimental investigation of phytoplankton nutrient limitation in two contrasting low arctic lakes
- 2006
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 1432-2056 .- 0722-4060. ; 29:6, s. 487-494
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Tidskriftsartikel (refereegranskat)abstract
- We investigated whether phytoplankton communities in two lakes in SW Greenland were phosphorus or nitrogen limited. The study lakes have contrasting water chemistry (mean conductivities differ ten fold) and are located near Kangerlussuaq, SW Greenland (similar to 67 degrees N, 51 degrees W). A microcosm nutrient enrichment experiment was performed in June 2003 to determine whether nitrate or phosphate addition stimulated phytoplankton growth. Samples were analysed for species composition, biomass, and alkaline phosphatase activity (APA). Initially, both lakes had extremely low total phosphorus but high total nitrogen concentrations and high APA, suggesting that the phytoplankton were phosphorus limited prior to the start of the experiment. The phytoplankton composition and biomass (mainly Ochromonas spp.) responded to phosphate but not to nitrate addition. In both lakes, chlorophyll a increased significantly when phosphate was added. Furthermore, APA was significantly lower in the two lakes when phosphate was added compared to the control and the nitrogen addition treatment. The dominance of mixotrophic pbytoplankton and high DOC values suggest that these lakes may be regulated by microbial loop processes.
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| 12. |
- Colesie, Claudia
(författare)
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Genus richness of microalgae and Cyanobacteria in biological soil crusts from Svalbard and Livingston Island: morphological versus molecular approaches
- 2018
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 41, s. 909-923
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Tidskriftsartikel (refereegranskat)abstract
- Biological soil crusts (BSCs) are key components of polar ecosystems. These complex communities are important for terrestrial polar habitats as they include major primary producers that fix nitrogen, prevent soil erosion and can be regarded as indicators for climate change. To study the genus richness of microalgae and Cyanobacteria in BSCs, two different methodologies were employed and the outcomes were compared: morphological identification using light microscopy and the annotation of ribosomal sequences taken from metatranscriptomes. The analyzed samples were collected from Ny-Alesund, Svalbard, Norway, and the Juan Carlos I Antarctic Base, Livingston Island, Antarctica. This study focused on the following taxonomic groups: Klebsormidiophyceae, Chlorophyceae, Trebouxiophyceae, Xanthophyceae and Cyanobacteria. In total, combining both approaches, 143 and 103 genera were identified in the Arctic and Antarctic samples, respectively. Furthermore, both techniques concordantly determined 15 taxa in the Arctic and 7 taxa in the Antarctic BSC. In general, the molecular analysis indicated a higher microalgal and cyanobacterial genus richness (about 11 times higher) than the morphological approach. In terms of eukaryotic algae, the two sampling sites displayed comparable genus counts while the cyanobacterial genus richness was much higher in the BSC from Ny-Alesund. For the first time, the presence of the genera Chloroidium, Ankistrodesmus and Dunaliella in polar regions was determined by the metatranscriptomic analysis. Overall, these findings illustrate that only the combination of morphological and molecular techniques, in contrast to one single approach, reveals higher genus richness for complex communities such as polar BSCs.
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| 13. |
- Convey, Peter, et al.
(författare)
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The importance of understanding annual and shorter term temperature patterns and variation in the surface levels of polar soils for terrestrial biota
- 2018
-
Ingår i: Polar Biology. - : Springer Publishing Company. - 0722-4060 .- 1432-2056. ; 41:8, s. 1587-1605
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Tidskriftsartikel (refereegranskat)abstract
- Ground temperatures in the top few centimetres of the soil profile are key in many biological processes yet remain very poorly documented, especially in the polar regions or over longer timescales. They can vary greatly seasonally and at various spatial scales across the often highly complex and heterogeneous polar landscapes. It is challenging and often impossible to extrapolate soil profile temperatures from meteorological air temperature records. Furthermore, despite the justifiably considerable profile given to contemporary large-scale climate change trends, with the exception of some sites on Greenland, few biological microclimate datasets exist that are of sufficient duration to allow robust linkage and comparison with these large-scale trends. However, it is also clear that the responses of the soil-associated biota of the polar regions to projected climate change cannot be adequately understood without improved knowledge of how landscape heterogeneity affects ground and sub-surface biological microclimates, and of descriptions of these microclimates and their patterns and trends at biologically relevant physical and temporal scales. To stimulate research and discussion in this field, we provide an overview of multi-annual temperature records from 20 High Arctic (Svalbard) and maritime Antarctic (Antarctic Peninsula and Scotia Arc) sites. We highlight important features in the datasets that are likely to have influence on biology in polar terrestrial ecosystems, including (a) summer ground and sub-surface temperatures vary much more than air temperatures; (b) winter ground temperatures are generally uncoupled from air temperatures; (c) the ground thawing period may be considerably shorter than that of positive air temperatures; (d) ground and air freeze–thaw patterns differ seasonally between Arctic and Antarctic; (e) rates of ground temperature change are generally low; (f) accumulated thermal sum in the ground usually greatly exceeds air cumulative degree days. The primary purpose of this article is to highlight the utility and biological relevance of such data, and to this end the full datasets are provided here to enable further analyses by the research community, and incorporation in future wider comparative studies.
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| 14. |
- Coulson, Stephen
(författare)
-
Distribution and population characteristics of the soil mites Diapterobates notatus and Svalbardia paludicola (Acari: Oribatida: Ceratozetidae) in High Arctic Svalbard (Norway)
- 2017
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 40, s. 1545-1555
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Tidskriftsartikel (refereegranskat)abstract
- The Oribatida of High Arctic Svalbard are faunistically relatively well known, but the distribution, density, stage structure and other population parameters of most species are unknown. Here we focus on two ceratozetid species, Diapterobates notatus (Thorell, 1871) and Svalbardia paludicola Thor, 1930, and investigate the summer density, stage and sex structure, proportion of gravid females and the body size of these species in 33 locations and 11 vegetation classes of Svalbard. Diapterobates notatus occurred in all vegetation classes and at 29 locations, whereas S. paludicola occurred in only two vegetation classes and at three locations. The common occurrence of D. notatus in Svalbard may be due to: (1) cosmopolitan nature of this species which inhabits all vegetation classes but with a preference for open Dryas/Carex rupestris communities, (2) high biological potential (females were more abundant than males and carried 6-7 large eggs) resulting in a high proportion of juveniles, and (3) juvenile morphology which possesses long setae that may enhance passive dispersal by the wind. Adult body size was found to be greatest in the floristically diverse Arctic meadows. Svalbardia paludicola was particularly abundant in the Arctic meadow at Reinsdyrflya where juveniles were more plentiful than the adults. The nymphs of this species have shorter gastronotal setae than those of D. notatus which may limit their passive transport by the wind. Scutozetes clavatosensillus Ermilov, Martens & Tolstikov, 2013 was found in Mosselbukta (north Spitsbergen); this is the first observation of this species in Svalbard.
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| 15. |
- Coulson, Stephen
(författare)
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No indication of arthropod-vectored viruses in mosquitoes (Diptera: Culicidae) collected on Greenland and Svalbard
- 2018
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 41, s. 1581-1586
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Tidskriftsartikel (refereegranskat)abstract
- Viruses transmitted to vertebrates via arthropod vectors (so-called arboviruses) include many important pathogens such as dengue virus, Zika virus, and Sindbis virus. Mosquitoes represent the major vectors of many of these arboviruses and occur in all climatic zones, including the Arctic. The focal species, Aedes nigripes (Diptera: Culicidae), is the most widely distributed mosquito species in the Arctic. We screened over 11,000 specimens collected between 2012 and 2016 on Greenland (Kangerlussuaq) and Svalbard (Petuniabukta) for the presence of arboviruses which have previously been reported in latitudes up to 70A degrees N. Assays for arbovirus detection using RT-PCR with primers specific for the genera Alphavirus (family Togaviridae), Orthobunyavirus, Phlebovirus (Bunyaviridae), Flavivirus (Flaviviridae), and Orbivirus (Reoviridae) were negative for all specimens. Similar results were recently obtained in a screening focused on tick-borne pathogens on Svalbard. The findings suggest that the circulation of arboviruses at studied localities is currently negligible or nonexistent, possibly due to dispersal, climate, or biotic restrictions. However, global climate change could enhance vector abundance and activity, introduction of invasive host species, and increase in tourism which then could lead to emerging arbovirus outbreaks in the future, with considerable impact on local ecosystems.
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| 16. |
- Coulson, Stephen
(författare)
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The Araneae of Svalbard: the relationships between specific environmental factors and spider assemblages in the High Arctic
- 2018
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 41, s. 839-853
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Tidskriftsartikel (refereegranskat)abstract
- As top predators in the Arctic invertebrate fauna, spiders in Svalbard are key components of the terrestrial ecosystem. However, most descriptions consist of observations of species occurrence and few repeated sampling campaigns investigating these heterogeneous assemblages, or the relationship between microhabitats and seasonality, exist. Spider assemblages were evaluated along four altitudinal transects (c. 10-300 m above mean sea level) on the west coast of Spitsbergen, Svalbard, throughout the summer of 2012. The slopes were selected to include most of the vegetation types typical for this region of Svalbard. Eleven of the known 15 native spider species were collected (10 Linyphiidae and 1 Gnaphosidae). We used Generalised Linear Models (GLM) for each spider species to identify the factors best explaining spider species abundance and distribution. The distribution of the majority of spider species was best described by vegetation or topography and none was accurately predicted by temperature. Only two species (Erigone arctica palaearctica and Hilaira glacialis) were common at all four sites and these two constituted 54% (1650 and 639 individuals, respectively) of the total spider individuals trapped. That assemblages of linyphiid spiders can differ greatly over small local and temporal scales further demonstrates the complexity of the Arctic terrestrial invertebrate community.
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| 17. |
- Coulson, Stephen
(författare)
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The terrestrial invertebrate fauna of EdgeOya, Svalbard: Arctic landscape community composition reflects biogeography patterns
- 2019
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 42, s. 837-850
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Tidskriftsartikel (refereegranskat)abstract
- Colonisation and immigration history is often neglected as a factor when investigating community or species distribution patterns. However, for dynamic systems that are still reacting to large-scale environmental change, such as the retreat of the ice since the last glacial maximum, colonisation history may explain a large amount of the variation between geographically distinct communities. The High Arctic archipelago of Svalbard presents an opportunity to test whether it is possible to observe the effects of large-scale biogeographical patterns on species distribution at landscape scales. Svalbard has one of the best described inventories of the invertebrate fauna in the Arctic. Nonetheless, the majority of the species records originate from the more accessible west coast and the invertebrate fauna of the whole eastern region, including EdgeOya, is virtually unknown. EdgeOya is located at the eastern fringe of the archipelago on the boundary between Palaearctic and Nearctic faunas. It was expected that post-colonisation dispersal within EdgeOya would conceal routes to the archipelago. Samples were obtained from six locations along the coast of EdgeOya between 2009 and 2010. 140 invertebrate species were identified belonging to 69 different genera of which 16 are new records for Svalbard. Most new species present an eastern Palaearctic distribution. Habitat variables (percentage cover of moss, lichen, vascular plant, or bare soil) fail to explain 35.5% of the differences among sites. However, cluster analysis reveals a clear east-west distribution pattern across the island suggesting that pan-Arctic dispersal routes can be identified even at relatively short geographical scales.
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| 18. |
- Dalerum, Fredrik, et al.
(författare)
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Spatial variation in Arctic hare (Lepus arcticus) populations around the Hall Basin
- 2017
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 40:10, s. 2113-2118
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Tidskriftsartikel (refereegranskat)abstract
- Arctic environments have relatively simple ecosystems. Yet, we still lack knowledge of the spatio-temporal dynamics of many Arctic organisms and how they are affected by local and regional processes. The Arctic hare (Lepus arcticus) is a large lagomorph endemic to high Arctic environments in Canada and Greenland. Current knowledge about this herbivore is scarce and the temporal and spatial dynamics of their populations are poorly understood. Here, we present observations on Arctic hares in two sites on north Greenland (Hall and Washington lands) and one adjacent site on Ellesmere Island (Judge Daly Promontory). We recorded a large range of group sizes from 1 to 135 individuals, as well as a substantial variation in hare densities among the three sites (Hall land: 0 animals/100 km(2), Washington land 14.5-186.7 animals/100 km(2), Judge Daly Promontory 0.18-2.95 animals/100 km(2)). However, pellet counts suggested that both Hall land and Judge Daly Promontory hosted larger populations at other times. We suggest that our results could have been caused by three spatially differentiated populations with asynchronous population fluctuations. With food limitation being a likely driver behind the observed variation, we argue that food limitation likely interacts with predation and competition in shaping the spatial dynamics of Arctic hares in this region.
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| 19. |
- Einarsdottir, Ingibjörg, 1951, et al.
(författare)
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Temperature influence on Arctic charr (Salvelinus alpinus L.) antibody response to a cellular antigen.
- 2000
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 23:4, s. 231-235
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Tidskriftsartikel (refereegranskat)abstract
- In order to elucidate the immune responses of Arctic charr in relation to temperature, groups were acclimated to a moderate (9 degrees C) and a cold temperature regime (4 degrees C), as well as subjected to a temperature decrease (from 9 to 4 degrees C) immediately prior to an immunization with sheep red blood cells. The charr kept at 9 degrees C responded with increased primary and secondary antibody titres, as seen by direct haemagglutination, while fish at 4 degrees C, as well as the fish subjected to a temperature reduction, displayed lower and lowest antibody titres, respectively, and only after a second immunization, It is concluded that Arctic charr can respond to a cellular antigen with a humoral immune response typical for other teleosts, but that the immune response is delayed and diminished at low temperatures. This temperature-induced immune suppression is intensified if the fish have not been acclimated to cold water prior to immunization.
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| 20. |
- Ekelund, Nils, 1956-
(författare)
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Studies on the effects of UV-B radiation on phytoplankton of Sub-Antarctic lakes and ponds
- 1992
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Ingår i: Polar Biology. - 0722-4060 .- 1432-2056. ; 12, s. 533-537
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Tidskriftsartikel (refereegranskat)abstract
- Experiments were performed to determine the effects of UV-B (ultraviolet, 280–320 nm) radiation on motility and growth of phytoplankton from lakes and ponds in South Georgia. After 4 h of solar radiation and 4h artificial radiation (UV-BBE 11.6 kJ m-2 day-1, UV-B lamps) the swimming velocity of Cryptomonas sp. decreased. The growth rate of Botryococcus, Lyngbya sp. and Stauraslrum sp. did not show any significant variations between the different light conditions. The UV-B component was reduced by filtering solar radiation through glass bottles und cellulose acetate. Cloudy days had only 30% of the radiation of clear days in both the PAR (photosynthetic active radiation) and UV-B regions. The ponds contained large amounts of humic substances, which are responsible for the absorbance in the UV region.
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| 21. |
- Elmhagen, Bodil, et al.
(författare)
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From breeding pairs to fox towns : the social organisation of arctic fox populations with stable and fluctuating availability of food
- 2014
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 37:1, s. 111-122
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Tidskriftsartikel (refereegranskat)abstract
- Food availability can impact group formation in Carnivora. Specifically, it has been suggested that temporal variation in food availability may allow a breeding pair to tolerate additional adults in their territory at times when food abundance is high. We investigate group occurrence and intraspecific tolerance during breeding in a socially flexible canid, the arctic fox (Vulpes lagopus). We compare Iceland and Sweden where resource conditions differ considerably. A breeding pair was the most common social unit in both populations, but as predicted, groups were more frequent where food abundance varied substantially between years (Sweden: 6 %) than where food availability was stable (Iceland: ≤2 %). Within Sweden, supplemental feeding increased group occurrence from 6 to 21 %, but there was no effect of natural variation in lemming (Lemmus lemmus) availability since group formation was rare also at lemming highs. Thus, additional factors appeared to influence the trade-off between intraspecific territoriality and tolerance. We report two cases where related females showed enduring social relationships with good-neighbour strategies. Related females also engaged in alloparental behaviour in a ‘fox town’ with 31 foxes (4 adults, 3 litters). In contrast, when unrelated foxes bred close to each other, they moved or split their litters during summer, presumably because of territorial conflict. We suggest that fluctuating food availability is linked to group formation in this Arctic carnivore, but also when food availability increases, additional factors such as relatedness, alloparental benefits, competition and predator defence appear necessary to explain group formation.
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| 22. |
- Gehrmann, Friederike, et al.
(författare)
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Sub-Arctic alpine Vaccinium vitis-idaea exhibits resistance to strong variation in snowmelt timing and frost exposure, suggesting high resilience under climatic change
- 2020
-
Ingår i: Polar Biology. - : Springer. - 0722-4060 .- 1432-2056. ; 43:10, s. 1453-1467
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Tidskriftsartikel (refereegranskat)abstract
- In tundra ecosystems, snow cover protects plants from low temperatures in winter and buffers temperature fluctuations in spring. Climate change may lead to reduced snowfall and earlier snowmelt, potentially exposing plants to more frequent and more severe frosts in the future. Frost can cause cell damage and, in combination with high solar irradiance, reduce the photochemical yield of photosystem II (ΦPSII). Little is known about the natural variation in frost exposure within individual habitats of tundra plant populations and the populations' resilience to this climatic variation. Here, we assessed how natural differences in snowmelt timing affect microclimatic variability of frost exposure in habitats of the evergreen Vaccinium vitis-idaea in sub-Arctic alpine Finland and whether this variability affects the extent of cell damage and reduction in ΦPSII. Plants in early melting plots were exposed to more frequent and more severe frost events, and exhibited a more pronounced decrease in ΦPSII, during winter and spring compared to plants in late-melting plots. Snowmelt timing did not have a clear effect on the degree of cell damage as assessed by relative electrolyte leakage. Our results show that sub-Arctic alpine V. vitis-idaea is currently exposed to strong climatic variation on a small spatial scale, similar to that projected to be caused by climate change, without significant resultant damage. We conclude that V. vitis-idaea is effective in mitigating the effects of large variations in frost exposure caused by differences in snowmelt timing. This suggests that V. vitis-idaea will be resilient to the ongoing climate change.
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| 23. |
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| 24. |
- Godoy, Erika, et al.
(författare)
-
Mating patterns in an inbred Arctic carnivore
- 2018
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 41:5, s. 945-951
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Tidskriftsartikel (refereegranskat)abstract
- Mating patterns are highly context-dependent and the outcome of selection pressures formed by ecological factors, inbreeding levels and access to available partners. In small and inbred populations, matings are limited by high kin encounter rates and access to mates. In this paper, we use background pedigree data to investigate mating patterns and inbreeding avoidance in an isolated and critically endangered Arctic fox (Vulpes lagopus) population. Empirical data showed avoidance of matings within natal family. Based on 35 documented matings, we only recorded two full-sibling matings and these occurred between individuals from different natal families. Matings between second-order relatives, however, occurred to the same extent as between unrelated individuals. To test how this influenced the population development of inbreeding (f), we simulated scenarios of random mating, exclusion of natal family and exclusion of individuals in already existing pair bonds. The observed development of inbreeding did not correspond the expected scenario of random mating (linear regression, r2 = 0.354, P = 0.20), but showed a comparable outcome as the simulated development of discriminating natal family (linear regression, r2 = 0.980, P < 0.001). We conclude that behavioural, pre-copulatory inbreeding avoidance strategies occur in this population and that exclusion of mating with natal family causes a slower increase in inbreeding levels compared to random mating. This study demonstrates how long-term monitoring, pedigree construction and simulations can generate information valuable for an in-depth understanding of both conservation genetics and behavioural ecology in threatened populations.
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| 25. |
- Gonzalez-Acuna, Daniel A., et al.
(författare)
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Parasites of chinstrap penguins (Pygoscelis antarctica) from three localities in the Antarctic Peninsula and a review of their parasitic fauna
- 2021
-
Ingår i: Polar Biology. - : Springer. - 0722-4060 .- 1432-2056. ; 44, s. 2099-2105
-
Tidskriftsartikel (refereegranskat)abstract
- Studies of parasitism in chinstrap penguins (Pygoscelis antarctica) are infrequent and mainly refer to the identification and description of its parasites, with little ecological data. In an attempt to address that lack of knowledge, we collected endo- and ecto-parasites from 326 live and four dead of chinstrap penguins, in three different localities of Antarctica not studied before. Three species of endoparasites and two of ectoparasites were found parasitizing birds: two tapeworms, Tetrabothrius pauliani (Cestoda: Tetrabothriidae) and Parorchites zederi (Cestoda: Dilepididae); one roundworm, Stegophorus macronectes (Nematoda: Acuariidae), and one feather louse: Austrogoniodes gressitti (Insecta: Phthiraptera: Philopteridae). Ticks (Ixodes uriae-Acari: Ixodidae) were collected from the ground near the penguin nesting colonies at two localities, Shirreff Cape and Narebsky Point. New ecological data are given for the two species of ectoparasites. No parasites were found in the blood collected from 300 live penguins.
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| 26. |
- Gonzalez-Acuna, Daniel, et al.
(författare)
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Health evaluation of wild gentoo penguins (Pygoscelis papua) in the Antarctic Peninsula
- 2013
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 36:12, s. 1749-1760
-
Tidskriftsartikel (refereegranskat)abstract
- Historically wildlife conservation was based on habitat protection and exploitation control. Only recently have diseases been considered an important issue. However, pathogens are usually described during or after disease outbreaks, but to determine which pathogens may be emerging, surveys of wildlife health are critical in a given time. This study deals with the health status of gentoo penguins Pygoscelis papua in two localities at the Antarctica Peninsula and one at Ardley Island off the South Shetland Islands. Cloacal swaps, fresh fecal samples, ectoparasites, and blood smears were collected. We examined and dissected 14 penguin corpses found dead. Fecal samples were positive for Campylobacter, Escherichia coli and in the carcasses four endoparasitic species were found: Diphyllobothrium sp. and Parorchites zederi, Corynosoma shackletoni and Stegophorus adeliae. The tick Ixodes uriae occurred in five of the examined penguins, and the louse Austrogoniodes gressitti on six birds. From the colony grounds, we collected 1,184 I. uriae. We recorded antibiotic-resistant bacteria, such as E. coli, in ecosystems where gentoo penguins breed. Cloacal samples (300) were negative for Chlamydia, as well as for Salmonella, Campylobacter, E. coli, Newcastle and Influenza viruses.
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| 27. |
- Graae, Bente Jessen, et al.
(författare)
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The effect of an early-season short-term heat pulse on plant recruitment in the Arctic
- 2009
-
Ingår i: Polar Biology. - : Springer Berlin/Heidelberg. - 0722-4060 .- 1432-2056. ; 32:8, s. 1117-1126
-
Tidskriftsartikel (refereegranskat)abstract
- Climate change will cause large-scale plant migration. Seedling recruitment constitutes a bottleneck in the migration process but is itself climate-dependent. We tested the effect of warming on early establishment of three Arctic pioneer species, while holding other environmental variables constant. Seeds and bulbils were sown in artificial gaps in dry Arctic tundra and subjected to a 13-day heating of the soil surface by 2-8°C, simulating temperature increases ranging from the general summer warming to heat waves projected to occur more frequently with global warming. All species showed decreased establishment with increasing soil surface temperature. The short-term heat pulse decreased establishment of Polygonum viviparum and Saxifraga cernua, whereas establishment of Cerastium alpinum decreased with temperature due to more permanent natural variation in micro-climate. The treatment effects increased by the quadrat of the temperature increase. Warming and in particular heat waves may result in declining establishment of Arctic plants in dry tundra regions. Electronic supplementary material The online version of this article (doi:10.1007/s00300-009-0608-3) contains supplementary material, which is available to authorized users.
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| 28. |
- Granquist, Sandra M., et al.
(författare)
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Fish consumption of harbour seals (Phoca vitulina) in north western Iceland assessed by DNA metabarcoding and morphological analysis
- 2018
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 41:11, s. 2199-2210
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding ecological relationships between humans and marine predators is crucial for the implementation of sustainable management practices. Comprehensive estimation of pinniped diet is essential for assessing interaction with fisheries and often has an important conservational value. Due to uncertainty regarding the accuracy of methods traditionally used to estimate harbour seal (Phoca vitulina) diet it is necessary to improve analysis methods. We investigated the diet of harbour seals hauling out in an estuary area in north-western Iceland between May and August of 2010 and 2011 by genetic (molecular) analysis of prey in faeces using DNA metabarcoding. The results were compared to previously published results from morphological analysis. Our results showed that species consumed were mainly sandeels (Ammodytes sp.), flatfishes (Pleuronectidae), gadoids (Gadidae), herring (Clupea harengus) and capelin (Mallotus villosus). The results from molecular and morphological analyses were similar in regards to important prey species, but species diversity was lower in the morphological analysis and 38% of the samples included prey items that were unidentifiable in the morphological analysis. Notably, despite Atlantic salmon (Salmo salar), brown trout (Salmo trutta) and Arctic char (Salvelinus alpinus) availability in the study area, neither of the methods found evidence of salmonids in the harbour seal diet. Recently, a severe decline has been observed in the Icelandic harbour seal population. Since the main reason for culling harbour seals in Iceland is to reduce predation on salmonids, findings presented in this paper have essential conservation implications and suggest that culling needs to be reassessed.
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| 29. |
- Granquist, Sandra Magdalena, 1979-, et al.
(författare)
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Seasonal, meteorological, tidal and diurnal effects on haul-out patterns of harbour seals (Phoca vitulina) in Iceland
- 2016
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 39:12, s. 2347-2359
-
Tidskriftsartikel (refereegranskat)abstract
- It is of critical importance to identify factors that affect harbour seal haul-out patterns to improve the accuracy of harbour seal censuses. In this study, haul-out patterns of harbour seals (Phoca vitulina) were investigated during different conditions at several major haul-out sites on Vatnsnes peninsula, NW Iceland (65400N and 20480W), over the 2008–2011 period. A seasonal haul-out pattern was detected among the seals, with the maximum number of seals on land found in July for most of the sites. Analyses of data for harbour seals on Vatnsnes indicate that the main pupping period occurs during late May to the beginning of June and moulting during late July to early August. Abundance at the sites increased with rising air temperature and decreased with increased windspeed and rising tides. However, no evidence that precipitation or cloud cover affected haul-out behaviour of the seals was detected. The diel haul-out pattern was investigated thoroughly in one of the haul-out sites and the results underlined the effect of tidal flucturation, air temperature and wind direction on the haul-out behaviour of harbour seals in the area. Results from this study can be used to improve the survey design when estimating the population size of harbour seals in Iceland and applied more broadly to the study of haul-out behaviour of harbour seals.
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| 30. |
- Gräns, Albin, 1979, et al.
(författare)
-
Effects of acute temperature changes on gut physiology in two species of sculpin from the west coast of Greenland
- 2013
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 36:6, s. 775-785
-
Tidskriftsartikel (refereegranskat)abstract
- For a fish to thrive, the gut must function efficiently. This is achieved through a range of processes, including controlled patterns of gut motility and modifications in gut blood flow. The knowledge of how gut functions in fish are affected by environmental temperature is sparse, and in order to understand how changes in climate may affect fish populations, we need to understand how gut blood flow and gut motility are affected by changes in temperature. By simultaneous recording of gut blood flow, gut motility, cardiac output, heart rate and cardiac stroke volume, in vivo at 4, 9 and 14 °C, the acute thermal sensitivity of a thermal generalist (shorthorn sculpin Myoxocephalu scorpius) was compared to the more strictly Arctic species (Arctic sculpin M. scorpioides). Temperature effects on gut motility were further explored in vitro, using isolated smooth muscles. Elevated water temperatures increased gut blood flow and contractile activity. Contraction frequency increased nearly threefold and gut blood flow almost doubled with the 10 °C increase. Both cardiac output and heart rate increased with temperature, while cardiac stroke volume decreased. The cholinergic agonist carbachol was most potent on smooth muscles at 9 °C. There were no differences between the two species, suggesting that the gastrointestinal and cardiovascular systems of Arctic sculpin, although a more pronounced Arctic species, have similar abilities to cope with acute fluctuations in water temperature as shorthorn sculpin. The impact of increased gut activity at higher temperatures needs further investigation before the effects of climate change can be predicted.
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| 31. |
- Gutt, J., et al.
(författare)
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Shifts in Antarctic megabenthic structure after ice-shelf disintegration in the Larsen area east of the Antarctic Peninsula
- 2013
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 36:6, s. 895-906
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to contribute to a general understanding of the response of the Antarctic macrobenthos to environmental variability and climate-induced changes. The change in population size of selected macrobenthic organisms was investigated in the Larsen A area east of the Antarctic Peninsula in 2007 and 2011 using ROV-based imaging methods. The results were complemented by data from the Larsen B collected in 2007 to allow a conceptual reconstruction of the environment-driven changes before the period of investigation. Both Larsen areas are characterised by ice-shelf disintegration in 1995 and 2002, respectively, as well as high inter-annual variability in sea-ice cover and oceanographic conditions. In 2007 one ascidian species, Molgula pedunculata, was abundant north and south of the stripe of remaining ice shelf between Larsen A and B. Population densities decreased drastically in the Larsen A between 2007 and 2011, coincident with the decrease in Corella eumyota, another ascidian. Among the ophiuroids, the population of deposit feeders increased, while suspension feeders halved their abundance. Current measurements indicated a northward flow between the Larsen B and Larsen A, suggesting that a major physical forcing on benthic population development comes from the South. The results demonstrate that Antarctic macrobenthic populations can exhibit dramatic population dynamics. Analyses of sea-ice dynamics, salinity, temperature and surprisingly ice-shelf disintegration history, however, did not provide any clear evidence for environmental drivers underlying the apparent changes.
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| 32. |
- Hansson, Lars-Anders, et al.
(författare)
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Food webs in sub-Antarctic lakes: a stable isotope approach
- 2003
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 1432-2056 .- 0722-4060. ; 26:12, s. 783-788
-
Tidskriftsartikel (refereegranskat)abstract
- In order to improve the understanding of food-web interactions in sub-Antarctic freshwater systems, we complemented earlier experimental studies with analyses of differences in stable isotopes (N-15 and C-13) among organisms in two lakes with contrasting productivity. The distribution of the stable isotopes showed that the small copepod Boeckella michaelseni feeds mainly on pelagic POM (particulate organic material), whereas the larger copepod species B. poppei also feeds on benthic algae. Furthermore, the predatory copepod Parabroteas sarsi seems to mainly feed on B. michaelseni, but also on B. poppei and the benthic cladoceran, Alona weineckii. Moreover, stable-isotope data suggest that the diving beetle, Lancetes angusticollis, is not only feeding on B. poppei as indicated from experimental studies, but also on the benthic cladoceran A. weineckii. Although the food webs of the two lakes are very similar, they show considerable differences in the distribution of stable isotopes. We conclude that monitoring, experiments and stable-isotope analysis in combination give a reasonably clear picture of sub-Antarctic freshwater food webs.
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| 33. |
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| 34. |
- Hernandez, Jorge, et al.
(författare)
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Enteropathogenic Escherichia coli (EPEC) in Antarctic fur seals Arctocephalus gazella
- 2007
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 30:10, s. 1227-1229
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Tidskriftsartikel (refereegranskat)abstract
- Rectal swabs were collected from Antarctic fur seal pups Arctocephalus gazella at Cape Shirreff, South Shetland Islands, and analyzed for the presence of anthropogenic pathogens. Two of the 33 pups tested positive for enteropathogenic Escherichia coli (EPEC). These samples are the first records of EPEC in Antarctic wildlife and suggest that more needs to be done to protect the Antarctic fauna from exotic anthropogenic pathogens.
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| 35. |
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| 36. |
- Holmgren, NMA, et al.
(författare)
-
Geographical variation in the timing of breeding and moult in dunlin Calidris alpina on the Palearctic tundra
- 2001
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 1432-2056 .- 0722-4060. ; 24:5, s. 369-377
-
Tidskriftsartikel (refereegranskat)abstract
- Studies of how organisms are adapted to regional climatic conditions are valuable when predicting the effects of global climatic changes on biota. Here we report on the geographical variation in timing of breeding and moult of an Arctic breeding wader, the dunlin (Calidris alpina). The Palearctic study sites range latitudinally between 68 and 76 degreesN and longitudinally between 46 and 179 degreesE, and encompass a variety of local climates. The sites were visited in sequence from west to east within 1 year, and therefore the data are not affected by confounding interannual variations. The estimated breeding start ranged from 5 to 25 June across populations. Birds at more southern sites were found to breed earlier than those at more northern breeding sites. Within populations, the breeding start for first clutches spanned a period of 8 days and, when including replacement clutches, 3-4 weeks. No dunlin west of the Taimyr Peninsula were found moulting while incubating at the nest, whereas all dunlin on Taimyr Peninsula and eastwards were in active wing moult while incubating or rearing chicks. The onset of moult in these populations ranged from 23 to 27 June. The consequences of geographical variation of breeding conditions for variation in the annual cycle of this species are discussed.
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| 37. |
- Ingimarsdottir, Maria, et al.
(författare)
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Corridor or drift fence? The role of medial moraines for fly dispersal over glacier
- 2013
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 1432-2056 .- 0722-4060. ; 36:7, s. 925-932
-
Tidskriftsartikel (refereegranskat)abstract
- Corridors are often considered to promote dispersal between habitat patches. In this paper, we study whether or not corridors induce colonisation of nunataks (ice-free areas in glacier surroundings) by promoting dispersal from lowland to the nunataks. On outlet glaciers, debris originating from nunataks forms the so-called medial moraines that stretch from the nunataks down-glacier to the lowland, forming corridors of debris on the glacier. Aerial dispersal was determined with yellow sticky traps on the moraines, bare glacier and glacier foreland. Dipterans were sampled in pitfall traps on the nunataks. Flying insects that were present on the vegetated glacier foreland belonged to five orders, that is, Diptera, Hemiptera, Hymenoptera, Lepidoptera and Trichoptera. On the glacier and medial moraines, however, mainly dipterans were present, with the majority of individuals found on the moraines. Hoverflies (Syrphidae) were abundant on the moraines and on the edges of nunataks close to the moraines, but were not present on the vegetated foreland. The origin of the hoverflies is thus not the nunataks and not the lowland. Rather, they are brought in by air currents towards the glacier, where they aggregate on a land type where they have a chance of survival, although it is not habitable. Thus, we conclude that the medial moraines do not function as regular corridors but as drift fences that direct the dispersal towards the adjacent land types, that is, the nunataks and the glacier foreland.
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| 38. |
- Isaksson, Jenny, et al.
(författare)
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Chlamydiaceae-like bacterium, but no Chlamydia psittaci, in sea birds from Antarctica
- 2015
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 38:11, s. 1931-1936
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Tidskriftsartikel (refereegranskat)abstract
- Within the growing order of Chlamydiales, there are a number of pathogens. One is Chlamydia psittaci, a zoonotic pathogen, with birds as natural hosts that may be transmitted to humans and cause severe respiratory disease, psittacosis. The prevalence of this pathogen in Antarctic birds is almost unknown as well as the ramifications of its potential spread in na < ve bird populations. To investigate the prevalence of chlamydia organisms, cloacal and fecal samples were collected from 264 penguins and 263 seabirds on the Antarctic Peninsula and in Southern Chile. No C. psittaci could be detected by 23S rRNA real-time PCR. However, DNA sequencing of the 16S rRNA 298-bp signature sequence revealed a Chlamydiaceae-like bacterium previously found in seabirds from the subarctic zone, demonstrating that this not yet fully characterized bacterium is widespread. In conclusion, the prevalence of C. psittaci among wild birds on the Antarctic Peninsula seems to be low, but other types of chlamydial organisms are common. Further studies are required to taxonomically define and finally understand the role of these non-classified Chlamydiae.
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| 39. |
- Kjellander, Petter, et al.
(författare)
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Body size in the Eurasian lynx in Sweden: dependence on prey availability
- 2010
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 33, s. 505-513
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Tidskriftsartikel (refereegranskat)abstract
- The Eurasian lynx (Lynx lynx) is a common predator of both roe deer (Capreolus capreolus) and reindeer (Rangifer tarandus) in Sweden. We investigated the influence of prey availability, latitude, sex, and age on body size and body mass variation of the Eurasian lynx in Sweden, using data from 243 specimens whose locality of capture, year of capture, sex, and age were known. We found that both body size and body mass of the lynx in Sweden are mainly affected by the lynx sex and age but also by the availability of prey during the first year of life. Body size and body mass of lynx as well as the density of roe deer increased from Central Sweden to South. Furthermore, body size and body mass of lynx increased from Central Sweden to North (i.e. within the reindeer husbandry area). Lynx body size was slightly smaller within the reindeer husbandry area (approximately north of latitudes 62A degrees-63A degrees N) compared to outside, probably because reindeer are more difficult prey to hunt, as well as being migratory and thus an unpredictable prey for the Eurasian lynx compared to the non-migratory roe deer. Our results support a growing body of evidence showing that food availability at growth has a major effect on body size of animals.
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| 40. |
- Kritzberg, Emma, et al.
(författare)
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Changes in Arctic marine bacterial carbon metabolism in response to increasing temperature
- 2010
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 1432-2056 .- 0722-4060. ; 33:12, s. 1673-1682
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Tidskriftsartikel (refereegranskat)abstract
- Arctic areas of deep-water convection have a large potential for export of organic carbon from surface waters into the deep sea and, therefore, are an important part of the global carbon cycle. As the Arctic is reportedly heating up faster than any other part of the planet, temperature-driven changes in the biogeochemical cycling in these areas can be very significant. Here, we study the regulation of bacterial carbon metabolism, which process vast amounts of organic carbon, by temperature and the availability of resources. The response of bacterial production and respiration of natural bacterial assemblages from the Fram Strait was studied by experimental manipulations of temperature and resources in combination. Both bacterial production and respiration were enhanced by temperature so that the total bacterial carbon demand increased sixfold following a temperature increase of 6A degrees C. Respiration responded more strongly than production so that bacterial growth efficiency decreased with increasing temperature. Although neither production nor respiration was limited by resource availability under in situ conditions, the response to temperature was higher in resource-amended treatments, indicative of a substrate-temperature interaction regulating both components of bacterial metabolism. In conclusion, the results show that warming can result in a substantial increase of the carbon flow through bacteria and that most of the carbon consumed would be released as CO2. Moreover, the results suggest that both temperature and availability of resources need to be considered to accurately be able to predict changes in bacterial carbon metabolism in response to climate change.
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| 41. |
- Ktitorov, Pavel, et al.
(författare)
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Shrub-dwelling species are joining the Arctic passerine bird community in the Chaun Delta (Western Chukotka, Russia)
- 2021
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 44:9, s. 1847-1857
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Tidskriftsartikel (refereegranskat)abstract
- Avian communities play a pivotal role in Arctic ecosystems and birds have become the key model taxa for climate change research. Due to funding priorities, Arctic passerines have been studied less intensively than waterfowl and shorebirds. In our study, we aim to partly fill this gap and look at the change in passerine community species composition in the Chaun River Delta in Northeast Siberia (68.81° N, 170.62° E) between 1970–1980 and 2002–2019. We restricted our comparison to 16 tundra-dwelling species associated with grass and shrub tundra habitats. During the first period, 12 passerine species were reported and by the end of the last period, 14 species. Our observations show that four species of shrub-dwelling passerines, the Dusky Warbler (Phylloscopus fuscatus), two species of Turdus thrushes, and the Siberian Rubythroat (Calliope calliope), have joined the local community. Additionally, one Turdus thrush species increased in numbers. The only passerine species that used to be common in the 70’s and rare in the 2000s is the Lapland Bunting (Calcarius lapponicus). Yellow-breasted Bunting (Emberiza aureola, vagrant in 70’s) and Siberian Chiffchaff (Phylloscopus tristis, rare breeder in 70’s) have not been recorded during the most recent period. At the same time, there was no observed change in abundance for eight species of songbirds. The results of supervised satellite image classification did not detect any local-scale increase of shrub cover in our study site. However, a broad-scale assessment of vegetation change using NDVI suggests substantial greening or ‘shrubification’ across the region. We speculate that it promotes region-wide increases and range expansion of some shrub-dwelling species, recorded in our study.
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| 42. |
- Kuparinen, J., et al.
(författare)
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Sea ice bacterial growth rate, growth efficiency and preference for inorganic nitrogen sources in the Baltic Sea
- 2011
-
Ingår i: Polar Biology. - : SPRINGER. - 0722-4060 .- 1432-2056. ; 34:9, s. 1361-1373
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Tidskriftsartikel (refereegranskat)abstract
- Seasonal Baltic Sea ice is structurally similar to polar sea ice and provides habitats for diverse ice organism assemblages that are integral to the biogeochemistry and ecology of the sea during winter. Temperature and inorganic nitrogen sources have been suggested to control bacterial growth, with increasing dependence on ammonium at low temperatures. To study the bacterial growth and preference for the nitrogen source, we conducted experiments at 0 and 4A degrees C, using ammonium and nitrate as nitrogen sources at two coastal fast-ice stations in the Gulf of Finland and in the Gulf of Bothnia during three successive winters. The two study sites differ markedly in relation to the allochthonous dissolved organic matter supply from the catchment area. High levels of bacterial growth were recorded at both study sites, with community generation times of 15-37 h. The measured bacterial growth efficiencies of 20-58% suggest that the Baltic sea ice brines provide a rich medium for bacterial growth and efficient functioning of bacteria-based food webs. Our experiments with sea ice samples showed a preference for ammonium at both temperatures and high potential growth in both types of nitrogen supplies. No major differences in phosphorus depletion rates were found at the two temperatures, but rates were always highest when ammonium was added to the experiments. These experiments point out that ice maturity, presumably through changes in bacterial community structure, impacts nitrogen processes and that these processes are pronounced prior to melting of the ice.
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| 43. |
- Larm, Malin, et al.
(författare)
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Fecal glucocorticoid metabolites as an indicator of adrenocortical activity in Arctic foxes (Vulpes lagopus) and recommendations for future studies
- 2021
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 44:10, s. 1925-1937
-
Tidskriftsartikel (refereegranskat)abstract
- Measuring fecal glucocorticoid metabolites (fGCMs) is a widely used, non-invasive method for studies of stress in vertebrates. To study physiological responses in wild Arctic foxes (Vulpes lagopus) to perceived stressors such as fluctuating food availability, occurrence of competitors and predators and disturbance from human activities, a species-specific physiological validation of a method to evaluate adrenocortical activity is needed. Here we used 15 captive Arctic foxes (both males and females and juveniles and adults) to investigate fGCM concentrations following ACTH injection (physiological validation), or handling alone and compared them with their respective baseline concentrations prior to the treatments. A 5 alpha-pregnane-3ss,11ss,21-triol-20-one enzyme immunoassay measured significant fGCM increases following both treatments. The time lags to reach peak fGCM values were 9.3 +/- 1.3 h and 12.8 +/- 1.7 h for ACTH and handling treatment, respectively. Concentrations of fGCMs varied a lot between individuals, but not attributed to sex nor age of the foxes. However, we found a negative relationship between boldness and fGCM concentrations. Faecal glucocorticoid metabolites concentrations did not change significantly over a period of 48 h in samples kept at temperatures reflecting winter and summer means. This would allow the collection of samples up to two days old in the wild regardless of the season. We conclude that our successfully validated method for measuring fGCMs can be used as a non-invasive tool for studies exploring various stressors both in wild and captive Arctic foxes.
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| 44. |
- Le Vaillant, Maryline, et al.
(författare)
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Spatial distribution in Norwegian lemming Lemmus lemmus in relation to the phase of the cycle
- 2018
-
Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 41:7, s. 1391-1403
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Tidskriftsartikel (refereegranskat)abstract
- Competition between individuals of the same or different species affects spatial distribution of organisms at any given time. Consequently, a species geographical distribution is related to population dynamics through density-dependent processes. Small Arctic rodents are important prey species in many Arctic ecosystems. They commonly show large cyclic fluctuations in abundance offering a potential to investigate how landscape characteristics relates to density-dependent habitat selection. Based on long-term summer trapping data of the Norwegian lemming (Lemmus lemmus) in the Scandinavian Mountain tundra, we applied species distribution modeling to test if the effect of environmental variables on lemming distribution changed in relation to the lemming cycle. Lemmings were less habitat specific during the peak phase, as their distribution was only related to primary productivity. During the increase phase, however, lemming distribution was, in addition, associated with landscape characteristics such as hilly terrain and slopes that are less likely to get flooded. Lemming habitat use varied during the cycle, suggesting density-dependent changes in habitat selection that could be explained by intraspecific competition. We believe that the distribution patterns observed during the increase phase show a stronger ecological signal for habitat preference and that the less specific habitat use during the peak phase is a result of lemmings grazing themselves out of the best habitat as the population grows. Future research on lemming winter distribution would make it possible to investigate the year around strategies of habitat selection in lemmings and a better understanding of a fundamental actor in many Arctic ecosystems.
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| 45. |
- Le Vaillant, Maryline, et al.
(författare)
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Telomere length reflects individual quality in free-living adult king penguins
- 2015
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 38:12, s. 2059-2067
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Tidskriftsartikel (refereegranskat)abstract
- Growing evidence suggests that telomeres, non-coding DNA sequences that shorten with age and stress, are related in an undefined way to individual breeding performances and survival rates in several species. Short telomeres and elevated shortening rates are typically associated with life stress and low health. As such, telomeres could serve as an integrative proxy of individual quality, describing the overall biological state of an individual at a given age. Telomere length could be associated with the decline of an array of physiological traits in age-controlled individuals. Here, we investigated the links between individuals' relative telomere length, breeding performance and various physiological (body condition, natural antibody levels) and life history (age, past breeding success) parameters in a long-lived seabird species, the king penguin Aptenodytes patagonicus. While we observed no link between relative telomere length and age, we found that birds with longer telomeres arrived earlier for breeding at the colony, and had higher breeding performances (i.e. the amount of time adults managed to maintain their chicks alive, and ultimately breeding success) than individuals with shorter telomeres. Further, we observed a positive correlation between telomere length and natural antibody levels. Taken together, our results add to the growing evidence that telomere length is likely to reflect individual quality difference in wild animal.
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| 46. |
- Leu, E., et al.
(författare)
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A (too) bright future? Arctic diatoms under radiation stress
- 2016
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 39:10, s. 1711-1724
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Tidskriftsartikel (refereegranskat)abstract
- Decreasing Arctic sea ice cover and increasing stratification of ocean surface waters make the exposure of pelagic microalgae to high irradiances more likely. Apart from light being a necessary prerequisite for photosynthesis, rapidly changing and/or high irradiances are potentially detrimental. An in situ study was performed in the high Arctic (79A degrees N) to determine the effect of high irradiances in general, and ultraviolet radiation (UVR, 280-400 nm) in particular, on cell concentrations, fatty acid composition, and photoprotective pigments of three diatom species isolated from seawater around Svalbard. Unialgal cultures were exposed in situ at 0.5- and 8 m-depth. After 40 h, cell concentrations of Synedropsis hyperborea and Thalassiosira sp., were lower at 0.5 than at 8 m, and the content of the photoprotective xanthophyll-cycle pigment diatoxanthin in all species (S. hyperborea, Thalassiosira sp., Porosira glacialis) was higher in the 0.5 m exposure compared to 8 m. In S. hyperborea, growth was additionally inhibited by UVR at 0.5-m depth. In situ radiation conditions led, furthermore, to a significant decrease in polyunsaturated fatty acids (PUFAs) in all three species, but UVR had no additional effect. Hence, we conclude that natural radiation conditions close to the surface could reduce growth and PUFA concentrations, but the effects are species specific. The diatoms' potential to acclimate to these conditions over time has to be evaluated.
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| 47. |
- Lindahl Rajala, Elisabeth, et al.
(författare)
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Prevalence of antibodies against Brucella spp. in West Greenland polar bears (Ursus maritimus) and East Greenland muskoxen (Ovibos moschatus)
- 2018
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 41, s. 1671-1680
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Tidskriftsartikel (refereegranskat)abstract
- Zoonotic infections transmitted from terrestrial and marine mammals to humans in European Arctic are of unknown significance, despite considerable potential for transmission due to local hunt and a rapidly changing environment. As an example, infection with Brucella bacteria may have significant impact on human health due to consumption of raw meat or otherwise contact with tissues and fluids of infected game species such as muskoxen and polar bears. Here, we present serological results for Baffin Bay polar bears (Ursus maritimus) (n=96) and North East Greenland muskoxen (Ovibos moschatus) (n=32) for antibodies against Brucella spp. The analysis was a two-step trial initially using the Rose Bengal Test (RBT), followed by confirmative competitive enzyme-linked immunosorbent assays of RBT-positive samples. No muskoxen had antibodies against Brucella spp., while antibodies were detected in six polar bears (6.25%) rendering a seroprevalence in line with previous findings in other Arctic regions. Seropositivity was not related to sex, age or biometrics i.e. size and body condition. Whether Brucella spp. antibodies found in polar bears were due to either prey spill over or true recurrent Brucella spp. infections is unknown. Our results therefore highlight the importance of further research into the zoonotic aspects of Brucella spp. infections, and the impact on wildlife and human health in the Arctic region.
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| 48. |
- Linnebjerg, Jannie Fries, et al.
(författare)
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Non-breeding areas of three sympatric auk species breeding in three Icelandic colonies
- 2018
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 41:10, s. 1951-1961
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Tidskriftsartikel (refereegranskat)abstract
- Like many seabirds, auks spend most of the year in offshore areas. Information on which oceanic areas they rely on throughout the winter is therefore important in understanding their population dynamics and establishing appropriate conservation measures. The breeding populations of Thick-billed Murres (Uria lomvia), Common Murres (Uria aalge) and Razorbills (Alca torda) in Iceland have been reported declining for the last 30 years. Thick-billed Murres have shown the most alarming rate of decrease, while Razorbills have declined the least. To help understand these changes, we collected information about the non-breeding distribution of these three species by using light-based geolocation. Geolocators were deployed on breeding adults in three different colonies in Iceland in 2013 and 2014. Data showed that the three species’ wintering areas differed substantially. Thick-billed Murres wintered off the west coast of Greenland and East Greenland/Northern Iceland, Common Murres favoured areas around Iceland/East Greenland and to the southwest along the Mid-Atlantic Ridge, and Razorbills were mostly distributed around Iceland. Although some intraspecific variation was evident, we conclude that the population development of Thick-billed Murres in Iceland is likely to be largely influenced by environmental conditions in west Greenland, while Common Murres and Razorbills are more dependent on the oceanic area around Iceland. The results may therefore prove to be an important platform for understanding the population dynamics of these three species in Iceland and informing conservation actions.
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| 49. |
- Low, Matthew
(författare)
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New methods and technologies for regional-scale abundance estimation of land-breeding marine animals: application to Adélie penguin populations in East Antarctica
- 2013
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 36, s. 843-856
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Tidskriftsartikel (refereegranskat)abstract
- Land-breeding marine animals such as penguins, flying seabirds and pinnipeds are important components of marine ecosystems, and their abundance has been used extensively as an indication of ecosystem status and change. Until recently, many efforts to measure and monitor abundance of these species’ groups have focussed on smaller populations and spatial scales, and efforts to account for perception bias and availability bias have been variable and often ad hoc. We describe a suite of new methods, technologies and estimation procedures for cost-effective, large-scale abundance estimation within a general estimation framework and illustrate their application on large Adélie penguin populations in two regions of East Antarctica. The methods include photographic sample counts, automated cameras for collecting availability data, and bootstrap estimation to adjust counts for the sampling fraction, perception bias, and availability bias, and are applicable for a range of land-breeding marine species. The methods will improve our ability to obtain population data over large spatial and population scales within tight logistic, environmental and time constraints. This first application of the methods has given new insights into the biases and uncertainties in abundance estimation for penguins and other land-breeding marine species. We provide guidelines for applying the methods in future surveys.
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| 50. |
- Machín, Paula, et al.
(författare)
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The role of ecological and environmental conditions on the nesting success of waders in sub-Arctic Sweden
- 2019
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 0722-4060 .- 1432-2056. ; 42:8, s. 1571-1579
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Tidskriftsartikel (refereegranskat)abstract
- Waders that breed in the sub-Arctic are one of the groups most threatened by climate change. At the same time, wader breeding success also can vary as a function of fluctuations in the numbers of predators and rodents (an alternative prey for the predators). How climate change could influence these foodweb interactions remains poorly studied. In this study, we analysed the effects of ecological (e.g. vole/lemming and predator abundance) and environmental factors (e.g. snow cover) on the breeding success of waders in sub-Arctic Lapland. We monitored more than 500 wader nests during six breeding seasons, which spanned a full rodent cycle and one year of exceptionally late snow melt. Nest predation rate, and thus wader breeding success, did not vary as a function of predator or rodent abundance. However, predation rate was exceptionally high in the year with a late snow melt. More variability in climate is expected for the future, where more precipitation and cold spring temperatures resulting in late snow melt will be more frequent, influencing the rodent and predator numbers, and therefore wader breeding success in the sub-Arctic. Snow would limit the number of open areas for nesting and hence predators would then be able to find these nests more easily. Additionally, predators might concentrate their efforts on alternative prey if snow has reduced their capacity to find other food sources. And, ultimately, changes in the rodent fluctuations could affect the final outcome of predators.
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