Polar Research (E-Journal)
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Triassic conodonts from Svalbard and their Boreal correlations
No full textConodont faunas are described from Triassic sections of Svalbard, and their occurrences are locally correlated with established ammonoid zones. With a synthesis of previous conodont-based publications, the current work presents a taxonomically up-to-date compilation of conodont data for the Triassic of Svalbard that is used to construct a conodont-based biochronology, indexed to the current lithostratigraphic nomenclature. Twenty-eight taxa spanning the earliest Griesbachian to the earliest Carnian are presented in a range chart. The examined conodont faunas are correlated with well-established conodont zonations of the Canadian Arctic, and in turn also form the basis for regional correlations
Wind-driven monthly variations in transport and the flow field in the Faroe–Shetland Channel
No full textThe transport of water from the North Atlantic to the Nordic seas through the Faroe–Shetland Channel is analysed from a decade of conductivity, temperature and depth (CTD) and acoustic Doppler current profiler (ADCP) data. The long-term mean transport, integrated over the upper 500 m, is 3.5 } 0.1 Sv (1 Sv = 10 6 m 3 s ? 1 ), of which 2.1 Sv is barotropic flow and 1.4 Sv is baroclinic flow. Short-term variability leads to a standard deviation of ca. 2.2 Sv in 3-day averages of the ADCP-measured transport. The barotropic transport is located over the upper part of the slope region of the Shetland Shelf, but sometimes broadens over deeper water. There is a peak surface baroclinic transport above the foot of the slope, and a weak recirculation of Modified North Atlantic Water (MNAW), which enters from the north, on the Faroese side. In September, when isobars downwell on the eastern side, the strong transport (ca. 4 Sv) is barotropic and evenly distributed across the Shetland slope, and both recirculation of MNAW from the Faroe side and mesoscale activity are weak. In spring, the net transport is small (ca. 2.5 Sv), the MNAW recirculation is strong and mesoscale activity is relatively large. These seasonal variations appear to correlate with the local south-west wind stress, which may contribute to nearly half of the long-term transport in the channel
Difference in diet and age structure of blue and white Arctic foxes (Vulpes lagopus) in the Disko Bay area, West Greenland
No full textThe stomach contents of 41 Arctic foxes (Vulpes lagopus) killed during winter and spring (December to June 1991–93) on Disko Island were examined. Fish, seabirds and marine invertebrates were found to be the most important winter food for Arctic foxes on Disko Island. Most fish remains in the stomachs were identified as capelin (Mallotus villosus), and cached fish appear to be important winter food for coastal foxes in the Disko Bay area. The stomachs of blue foxes contained more fish and marine invertebrates than those of white foxes, and stomachs of blue males contained more fish than those of blue females and white foxes of either sex. The age of 26 foxes was determined by X-rays and counting of annual lines in canine root cementum. Almost all the white foxes but less than a quarter of the blue foxes were in their first winter when harvested. The results of this study suggest that most of the white foxes were immigrants to Disko Bay while the blue foxes originated locally
Late Quaternary marine-based Kara Sea ice sheets: a review of terrestrial stratigraphic data highlighting their formation
No full textReconstructions of the Late Quaternary glacial history of the Kara Sea area show repeated build-up of ice-sheet domes over the shallow epicontinental Kara Sea. Inferred ice divides were situated over the central Kara Sea, and the ice sheet repeatedly inundated the surrounding coastal areas of western Siberia. Geological fingerprinting of the Kara Sea ice sheet include end moraine zones, raised beaches, tills, glaciotectonic deformations and coarsening-upward sediment sequences, reflecting isostatic rebound cycles. This paper reviews evidence from several areas along the perimeter of the Kara Sea, suggesting that peripheral sites were critical for the initiation of the large Kara Sea ice sheet. Ice-sheet inception progressed with the formation of local ice caps that later coalesced on the adjacent shelf with globally falling sea levels, eventually merging and growing into a large ice dome
Intraspecific variation of Svalbardiceras spitzbergensis (Frebold) from the Early Triassic (Spathian) of Spitsbergen
No full textThe ammonoid species Svalbardiceras spitzbergensis from the latest Early Triassic (Spathian, subrobustus Zone) shows a remarkable intraspecific variation. The more than 400 specimens studied come from one fossiliferous carbonate nodule layer within a sequence of mudstones and clayey siltstones of the Vikinghøgda Formation (Vendomdalen Member), mainly collected in the Sassendalen and Agardhbugta areas in central and eastern Svalbard, respectively. The preservation of the ammonoids is very good, usually with preserved shells and complete body chambers. Morphologically they range from compressed, more or less smooth platycones, with narrow umbilicus, to wide umbilicate, depressed forms with straight, prominent ribs. The morphological variation is continuous: all specimens belong to a single assemblage, and are variants of one biospecies. This phenomenon, which is quite common in Boreal Triassic ammonoid faunas, has in the past led to serious taxonomic oversplitting. Furthermore, this new example presents a serious challenge to current ideas about the close correlation between mode of life and shell morphology of ammonoids
Late Permian to Middle Triassic palaeogeographic differentiation of key ammonoid groups: evidence from the former USSR
No full textPalaeontological characteristics of the Upper Permian and upper Olenekian to lowermost Anisian sequences in the Tethys and the Boreal realm are reviewed in the context of global correlation. Data from key Wuchiapingian and Changhsingian sections in Transcaucasia, Lower and Middle Triassic sections in the Verkhoyansk area, Arctic Siberia, the southern Far East (South Primorye and Kitakami) and Mangyshlak (Kazakhstan) are examined. Dominant groups of ammonoids are shown for these different regions. Through correlation, it is suggested that significant thermal maxima (recognized using geochemical, palaeozoogeographical and palaeoecological data) existed during the late Kungurian, early Wuchiapingian, latest Changhsingian, middle Olenekian and earliest Anisian periods. Successive expansions and reductions of the warm– temperate climatic zones into middle and high latitudes during the Late Permian and the Early and Middle Triassic are a result of strong climatic fluctuations
Changes at Peter I Øy
No full textPeter I Øy, a remote Norwegian territory, is one of the most rarely visited of the peri-Antarctic islands. Since the last Norwegian research visit, in 1987, approximately 10 tourist ships have been to the island, and about half of these have made landings. Where practical, reports have been sent to the Norwegian Polar Institute and other interested parties. I have made five visits, landing during four of them, while employed by Quark Expeditions to lecture on Antarctic history and geography aboard Kapitan Khlebnikov . My most recent visit, on 21 November 2006, demonstrated the continual geological erosion of the coast. In 2004 at Pingvinholet there was a splendid triple natural arch: the outer arch was formed by black basaltic deposits, and the inner one was capped by a stratum of red oxidized larva. The third arch was the result of a basalt flake slipping and propping itself against the middle column. The sea penetrated through all three arches so that it would have been possible, although reckless, to take a small boat through the largest of them. In late 2006, while sailing from South America to New Zealand near the Antarctic coast, I noted the entire inner section had collapsed. Only one large arch now remains and this no longer admits the sea. The collapse of both the cap of red larva and supporting pillar has formed a pile of rubble several metres above the sea
Eastward moult migration of non-breeding pink-footed geese (Anser brachyrhynchus) in Svalbard
No full textSix adult male pink-footed geese ( Anser brachyrhynchus ), tagged with satellite transmitters, were tracked in Svalbard during the period of June–September in 2003 and 2004. The purpose of the study was to describe the movements and staging periods of individual geese during the post-breeding period to investigate a possible moult migration among pink-footed geese in Svalbard. All geese moved about 200 km east from their potential breeding (summering) areas in western Spitsbergen. The preferred moulting area was the island of Edgeøya, where four geese staged prior to a southward autumn migration. Five geese left potential breeding areas between 11 and 30 June, and remained for more than 25 days in eastern areas during most of July, which we interpret as the moult migration of either failed or non-breeders. Geese left moulting areas in mid-August, using an average of 1.4 staging areas before the autumn migration, suggesting that moult sites support pre-migration hyperphagia. Only one goose remained at the suspected breeding site from early June to early September. Mean monthly temperatures in the summering and moulting ranges of the geese were calculated from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data. The mean June moult range temperature ( ? 0.9 ° C) was significantly lower than that of the summering ranges (4.6 ° C). The July mean moult range temperature did not differ significantly from that in June on the summering ranges. We contend that failed or non-breeding pink-footed geese move eastward in Svalbard to exploit the early stages of summer plant growth as a result of the delayed thaw compared with central and southern Spitsbergen
Health in the Arctic and climate change
No full textThe Arctic environment is like a magnifying glass. Many of the hazards stemming from industrial activity in the South tend to concentrate in the North. This is true for DDT, PCB, heavy metals and many other substances that may endanger human health. Climate change is yet another example of how the negative impact of industrial activity may be magnified in the Arctic region
Distribution of demersal fish in the south-western Barents Sea
No full textThe composition of the demersal fish fauna of the Barents Sea, and the ranges of most of the fish species, have been relatively poorly known. From 257 bottom trawl hauls distributed in a uniform grid pattern over the southwestern part of the Barents Sea in summer 2000, all fish were identified. The sampled area included the Polar Front zone where warm Atlantic water meets cold (subzero) polar water. The material was used to map the distribution of the demersal fish species, and to analyse their distribution in relation to temperature, depth and salinity. Fifty-eight species were recorded. A fauna characterized by Gadidae and Scorpaenidae was found in the warmer part of the sea, whereas a cold-water fauna of mainly Cottidae, Zoarcidae and Stichaeidae was evident from the Polar Front zone and northwards. In logistic regression analyses temperature was the most important factor associated with the distribution of species (for 26 of the 27 species analysed), but associations with salinity (19 species) and depth (15 species) were also found. The mapping considerably revised the distribution in relation to previous knowledge for 37 species, and the new and more accurate range maps provided here may serve as baseline information for future monitoring of the fish fauna in the Barents Sea