Polar Research (E-Journal)
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Hydrographic and current measurements in the Fram Strait, August 1981
No full textThe hydrographic (CTD) observations and pendulum current measurements obtained with M/S 'Lance' in August 1981 in the area west and north of Spitsbergen, are presented. The warm and saline northward flow, known as the West Spitsbergen Current, is found to follow the shelf break. In the Fram Strait the hydrographic structure is complicated because of eddies and other transient movements. The current measurements suggest a two-layer structure where the velocity vector rotates in opposite directions in the two layers with a period near the semidiurnal tidal period
Arrival and pre-nesting period of the snow bunting Plectrophenax nivalis in East Greenland
No full textThe first snow bunting males arrive in Northeast Greenland in early April, 6-8 weeks before nesting and 2 4 weeks ahead of the females. At this time temperatures regularly reach -25 to -30°C and snow storms may rage for days. The living conditions during this long-lasting pre-nesting period and its possible function are described and discussed. Based on 781 birds caught. .ringed, and measured, and on observations on phenology, diurnal rhythm, night roosts, etc., it is shown that the age ratio in males is close to 50/50 first living year/adults, that adult males arrive and occupy territories earlier than first year males, that first-year males have shorter wings and are leaner than adult males, that the birds lose weight during spells of inclement weather early in the season, that diurnal rhythm is apparently governed by direct insolation, that males apparently greatly outnumber females in the populations, and that competition for the optimal territories is probably the selective force behind the prolonged pre-nesting period in males
Additional evidence of pre-Silurian high-pressure metamorphic rocks in Spitsbergen
No full textIt has been previously suggested that the high-pressure metamorphic rock complcx of Motalafjclla. central-western Spitsbergen, is older than Lower Silurian. An unconformity has been discovered at the base of a limestone which contains fossils similar to those reported as Lower Silurian from the same massif. This proves that the high-pressure metamorphics represent an older rock complex. The unconformity surfacc is invcrted in the area, and large recumbent folds involving the Silurian Bulltindcn Formation havc been mapped. These folds are considered to be prc-Carboniferous
Synergistic effects of an oil dispersant and low temperature on the freezing tolerance and solute concentrations of the blue mussel (Mytilus edulis L.)
No full textExposure of blue mussels (Mytilus edulis L.) to an oil dispersant in increasing concentrations caused increased degree of injury in the mussels. The oil dispersant seemed to affect mechanisms responsible for the distribution of inorganic ions (Na+, K+, Cl-) and free amino acids across the cell membranes. The dispersant caused a marked reduction in the ability of the mussels to survive freezing at -10°C. Freezing also caused more pronounced alterations in the transmembrane ionic distributions observed following exposure to the dispersant. This may indicate that the injuries caused by freezing are qualitatively the same as those caused by exposure to the dispersant alone, but brought into more extreme conditions. Thus, freezing appears to potentiate the effect of environmental pollutions by concentrating them in the fluid fraction of the frozen body fluids
Overwintering of Vaccinium vitis-idaea in two sub-Arctic microhabitats: a reciprocal transplantation experiment
No full textNorthern plants have to cope with a wide range of overwintering conditions, as the depth and physical properties of snow show high spatial variation in the Arctic. The overwintering of lingonberry (Vaccinium vitis-idaea) was studied in a reciprocal transplantation experiment between two sub-Arctic microhabitats in northern Finland. The experiment was set up in the autumn, and physiological traits related to overwintering were measured at the time of snowmelt in the following spring. The origin of the plants was not a significant source of variation for most of the traits measured, whereas major differences were observed between the two sites. Plants that overwintered at an exposed site above the treeline showed high relative winter damage, assessed by the electrolyte leakage of the leaves. No severe winter damage was observed in the plants that overwintered under a moderate snowpack at a sheltered birch forest site. These plants were able to maintain their photosynthetic capacity through the winter. A low capacity of photosystem II and a very low capacity of CO2 uptake were characteristic of the exposed site, where low temperatures and high irradiation predominate during late winter. However, photosynthetic capacity was recovered within a few days when the plants were kept under favourable conditions after the field experiment. The content of nonstructural carbohydrates was low, probably because of high respiratory losses under the snow. This short-term study suggests that lingonberry, which occupies a wide range of microhabitats in the present climate, may thrive even if the overwintering conditions change as a result of climatic warming
Neoproterozoic metamorphic evolution of the Isbjørnhamna Group rocks from south-western Svalbard
No full textA metamorphosed volcano-sedimentary complex constitutes the Caledonian basement in the south-western part of Wedel Jarlsberg Land, Svalbard. Field, textural and previous thermochronologic data indicate a weak, localized metamorphic Caledonian overprint (M2). Deformed M1 isograds and variation in pressure–temperature estimates indicate a pervasive Neoproterozoic amphibolite-facies metamorphism that pre-dates large-scale Caledonian age folding. Garnet–biotite and garnet–Al silicate–plagioclase (GASP) geothermobarometry of the Isbjørnhamna Group mica schists, and their comparison with the K2O–FeO–MgO–Al2O3–SiO2–H2O (KFMASH) petrogenetic grid, indicates a peak pressure of ca. 11 kbar, and a peak temperature of ca. 670°C during M1 metamorphism. A cooling rate of ca. 5°C My-1 is estimated on the basis of geothermobarometry and the available U–Th–total Pb and Ar–Ar data
Fram Strait sea-ice sediment provinces based on silt and clay compositions identify Siberian Kara and Laptev seas as main source regions
No full textFram Strait sea-ice sediments (SIS) contain on average more than 94% silt and clay. Both fractions were compared with bottom deposits of the Kara and Laptev seas to identify shelf sources of fine-grained Arctic SIS. Based on silt granulometry and clay mineral assemblages we determined Fram Strait SIS provinces. Western Fram Strait SIS has medium to fine silt compositions, whereas eastern Fram Strait SIS is enriched in fine silt.Western Fram Strait SIS clays (low smectite/high illite) were statistically grouped with eastern Laptev shelf deposits, and are similar to East Siberian and North American shelf sources. Eastern Fram Strait SIS clays (high smectite/low illite) cluster with shelf deposits of the western Laptev Sea and the Kara Sea. We conclude that western Fram Strait pack ice consisted of a mixture of floes from the Laptev Sea and sources farther to the east during the 1997 and 1999 sampling periods. Eastern Fram Strait ice originated from sources towards the Kara Sea. There was an average annual flux of ca. 158 Tg (Mt) SIS export through Fram Strait during the late 1990s.We expect no qualitative changes in the SIS entrainment process (“suspension freezing”) with decreasing Arctic ice cover, although the process may increase through larger fetch. SIS incorporation and flux will be enhanced with increasing shelf open water during winter freezing, and with the current acceleration of the Transpolar Drift, but we speculate that the transport of SIS towards Fram Strait will be seasonally truncated with the onset of ice-free summers in the Arctic Ocean
Melting sea ice for taxonomic analysis: a comparison of four melting procedures
No full textThe influence of four melting procedures on the taxonomic composition of the sea-ice algal community in Kobbefjord, south-west Greenland, was investigated in April 2008. Direct melting (at 4 and 20°C) was compared with melting in buffering seawater (with salinities of 10 and 30). The sea-ice algal community consisted of diatoms, cysts and several flagellate groups. Direct melting at 20°C differed significantly from one or more of the other melting procedures regarding the flagellate groups chrysophytes, chlorophytes, dinoflagellates and unidentified flagellates, whereas diatom, cyst and cryptophyte abundance was similar, regardless of the melting procedure. Apart from chrysophytes, the three other melting procedures (direct melting at 4°C and buffered in seawater with salinities of 10 and 30) were not statistically different. It is recommended that direct melting at 20°C is avoided, whereas the three slow melting procedures are all comparable. This will enable the future comparison of data from a wide geographic and historical range, thereby increasing our knowledge of sympagic algal communities
Review of Legacies and change in polar sciences: historical, legal and political reflections on the International Polar Year, edited by JM Shadian & M Tennberg
No full textThe International Polar Year (IPY) of 2007–09 was an international scientific enterprise that encompassed all polar regions, and built on the legacies bequeathed by earlier endeavours stretching back to the late 19th century. The first such venture was initiated in 1882–83, the second was in 1932–33 and the last, the International Geophysical Year (IGY), occurred in 1957–58, and involved thousands of scientists working inter alia in the polar continent. Activity in the Arctic, for geopolitical reasons, was rather more limited, and was certainly not epitomized by free and unfettered scientific investigation. Sponsored by the International Council for Science, the most recent IPY was noteworthy for its explicit bi-polar focus, and its integration of the humanities and social sciences with the physical and environmental sciences. The role of indigenous communities was also notable in Arctic-based projects, a development that would have been inconceivable during the IGY. As with the IGY, however, a spectacular event in one of the theatres of scientific interest grabbed world headlines: in 1957 it was Sputnik orbiting the Earth, and in 2007 it was a Russian submersible planting a flag on the bottom of the central Arctic Ocean basin
Atmospheric controlled freshwater release at the Laptev Sea continental margin
No full textConsiderable interannual differences were observed in river water and sea-ice meltwater inventory values derived from d18O and salinity data in the Eurasian Basin along the continental margin of the Laptev Sea in the summers of 1993 and 1995, and in the summers of 2005 and 2006 during Nansen and Amundsen Basins Observational system (NABOS) expeditions. The annually different pattern in river and sea-ice meltwater inventories remain closely linked for all of the years studied, which indicates that source regions and transport mechanisms for both river water and sea-ice formation are largely similar over the relatively shallow Laptev Sea Shelf. A simple Ekman trajectory model for surface Lagrangian particles based solely on wind forcing can explain the main features observed between years with significantly different wind patterns and vorticities, and can also explain differences in river water distributions observed for years with a generally similar offshore wind setting. An index based on this simplified trajectory model is rather similar to the vorticity index, but reflects the hydrology on the shelf better for distinctive years. This index is not correlated with the Arctic Oscillation, but rather with a local mode of oscillation, which controls the outflow and distribution of the Eurasian Basin major freshwater source on an annual timescale. Keywords: Arctic Ocean halocline; atmospheric forcing; Laptev Sea; stable isotopes; water masses. (Published: 1 January 2011) Citation: Polar Research 2011, 30: 5858 - DOI: 10.3402/polar.v30i0.585