The ostracod fauna were examined from the Kapp Starostin Formation sequences (Upper Permian) from West Spitsbergen (Svalbard). The ostracod taxa are mainly confined to 3 superfamilies: Kirkbyacea, Healdiacea and Bairdiacea. 11 taxa are identified. One new species, Kindlella bellsundi is proposed. The ostracod assemblage dominated by kirkbyacean taxa is related to open shelf marine environment.
Epifaunal organisms (bryozoans, foraminifera, serpulid polychaetes, cirripeds, octocorals), scratch marks and borings (brachiopod pedicle attachment traces and gastropod, phoronid, sponge and algal boreholes) were recognized on the brachiopod shells from the Eocene La Meseta Formation of Seymour Island, Antarctic Peninsula. They are rare and occur only on about 10% of shells. It is probable that environmental conditions were not suitable for epibionts whose requirements were to be higher than those of brachiopods. The rarity of epifauna on the dead shells can be explained by their rapid burial.
Comparison of T and S values in areas 1, 2, and 3 in the Bransfield Strait and Admiralty Bay (Fig. 1) shows that the warmest waters are found in area 1, while the coldest in area 3. Surface salinity is the lowest in area 2 as a result of water outflow from land. In area 3 vertical salinity variations are the lowest, with the maximum occurring at the surface. At 500 m depth the highest salinity is recorded in area 1. The most homogeneous distribution of temperature and salinity is observed in area 3. In Admiralty Bay, in the annual cycle of 1995 water temperatures at 4 m, 10 m and 100 m are similar to those in 1979 except in the winter, when they are lower.
Temperature of superficial water in the Ezcurra Inlet was measured from March 1989 to February 1990, with a use of a mercurial thermometer with accuracy +0.1°C. Temperature was measured usually once a month at selected points. Influence of various factors on temperature of superficial water was preliminarily analysed. Basing on these results, temperature distribution in the mentioned area was determined. Mean yearly temperatures for each station, average space temperatures on measurement days and mean yearly temperatures for the whole area of the Ezcurra Inlet were calculated.
Complex analysis ofgeomorphological glacial processes in forefields of retreating glaciers in the southern Bellsund region was undertaken. Field studies and archival cartographic materials indicate continued glacial retreat, at least since the turn of the 19th and 20th centuries. Its average present rate of about 20 m/y is rather high and no moraine ridges are formed, except for the fluted moraines. Forefields of large glaciers are characterized by typical relief and sediments of frontal deglaciation only. Intensity and extent of glacial forefield remodelling depends mainly on activity ablation waters. At present glaciofluvial erosion predominates.
Mountain soils derived from massive rocks were studied in the northwestern Wedel Jarlsberg Land. Main soil properties were examined for collected samples. Soils were classified as lithosols with common loamy and silty composition, and small amount of colloidal fraction. Soils were mostly alkaline due to high content of CaCO3. Much more organic substance occurred at westerly- than easterly-exposed hills and located close to a sea. Examined soils contained much soluble forms of Ca, Mg and occasionally Na, little of P and K. Density of plant cover corresponded to contents of organic substance.
Soil-plant conditions in selected valleys typical for Bellsund Region are varying from hardly favourable (Skilvika), to favourable (Calypsostranda) and medium (Lyellstranda). Plant growth and development of a soil cover are favoured by grain size composition (loamy sands and light loams), quick warming-up of a soil, relative stability of a ground, location and shape of valleys, etc. Unfavourable soil-plant conditions result from too light or too heavy grain size composition, considerable dynamics of ground mechanical features and high compactness of a soil. Varying contents of carbonates and alkaline reaction (except for almost neutral reaction in organic horizons) were typical for the studied soils. Thickness of humus horizons as well as contents of organic C vary at the three studied sites. Significant is high concentration of easily available Ca and Mg, sometimes also of Na.
The Polish geological research on King George Island, South Shetland Islands (West Antarctica), during the two past decades (1977-1996) included: stratigraphy, radiometric dating, petrology and geochemistry, sedimentology and palaeoenvironmental studies, volcanology, tectonics, structural geology, Quaternary geology, paleobotany and palaeozoology. The major scientific achievements were: (1) the establishment of formal lithostratigraphic standards for radiometrically-dated Upper Cretaceous through Tertiary magmatic rock sequences and intercalated sediments; (2) the discovery of four Tertiary glaciations and three interglacials, spanning some 30 Ma from Early/Middle Eocene through Early Miocene; (3) the discovery and systematic elaboration of rich terrestrial and marine biota of Late Cretaceous through Early Miocene ages; (4) the reconstruction of changing Late Cretaceous and Tertiary terrestrial and marine palaeoenvironments in a mobile volcanic-arc setting; (5) the determination of age and structural evolution of the island's two Quaternary volcanoes; (6) the reconstruction of the Late Cretaceous through Recent evolution stages of the South Shetland magmatic arc and its backarc Bransfield Basin and Rift, based on tectonic and structural studies.
Luticola muticopsis is a characteristic species of polar and subpolar regions. Its morphological variability is not yet precisely described. In the investigated population the cells from capitate to shortened, flat rounded tips were observed. The range of dimensions of specimens was 8.8-40.6 μm x 5.5-17.6 μm, striae 11-22/10 μm; this range considerably exceeded that found in holotype diagnosis.
A year-round (3 March 1994 - 28 February 1995) phytoplankton study in Admiralty Bay revealed nanoplankton flagellates (< 20 μm) to be the major algae of the plankton, both in terms of cell numbers and carbon biomass. Their quantities fluctuated widely thoroughly the year showing several peaks, in May, April, December and January. Summer maximum of the group in December was mainly due to Cryptophyceae (4.9 x 106 cells l-1; 98.0 μg C 1-1) and Prasinophyceae (7.3 x 105 cells -1; 33.5 μg C -1). Diatoms were usually scarce (max. 6.8 x 105 cells -1; 7.82 p:g C 1-1) and were dominated by small species of Thalassiosira and by Nitzschia spp. (Pseudonitzschia); the domination structure somewhat differed from that observed in Admiralty Bay in the summer of 1977/78. Algal peaks were related to the surface water (4 m depth) temperature rise from +0.16 to +1.71˚C. Summer phytoplankton maxima were about 5-fold greater than those recorded in the summer of 1977/78.
A lichenicolous fungus, Dactylospora dobrowolskii Olech et Alstrup, new to science is described. The paper reports on 9 species of lichens and lichenicolous fungi collected in the Bunger Oasis (East Antarctica).
The highest infestation by phoronts (resting stages) of Apostoma ciliates forms 1, 2, is restricted to the 3-th and 4-th pairs of E. superba thoracic limbs. They occur mostly on meropodites of endopodite and plumose setae of exopodite. The trophonts (trophic stage) of those Apostoma are present in large numbers in krill's tissue. The life cycle of those histophagous Apostoma include also free-living stage - tomit. Swarm formed by krill seems to be a reason for the common and extensive infestation by protozoans.
Nematoda, Tardigrada, Rotifera and Crustacea composition in different freshwater habitats on Spitsbergen (Arctic) and King George Island (Antarctic) was presented. In all surveyed groups more genera and species were recorded from Spitsbergen than from King George Island. Habitats richest in taxa were moss banks and thaw ponds, whereas streams were poorest in species. In all groups in both regions cosmopolitan species dominated, but higher number of endemic species was recorded on King George Island. Regarding species composition in surveyed groups it can be suggested that freshwater habitats on Spitsbergen are more similar to each other than those on King George Island.
A collection of 15 283 individuals of tanaidacean crustaceans was gathered by successive Polish Antarctic Expeditions in the years 1977-1993 in Admiralty Bay (King George Island, South Shetland Islands). Twelve species belonging to three families are identified in this study. The material is clearly dominated by Nototanais antarcticus (Hodgson, 1902); other common species were Nototanais dimorphus (Beddard, 1886) and Peraeospinosus sp. A. The highest density of tanaids was over 140 000 specimens m-2 , occuring on a muddy bottom in Herve Cove lagoon.
Traps to catch microfauna transported by wind were installed on already colonised by plants area, in the vicinity of the glacier. After 6-week-exposition 859 individuals of microfauna were caught, of which Nematoda constituted 71%, Tardigrada 22% and Rotifcra 7%. Number of microfauna individuals caught depended on distance from the already colonised areas and presence of plant parts, together with which animals can be transported more easily. Microfauna connected with vegetation, which is transferred together with plant parts, was transported in higher numbers. Probably these taxa (i.e. Diphascon within tardigrades and Dorylaimidae within nematodes) colonise new habitats at first, but other species dominate later in freshwater bodies.
Herve Cove, a small, shallow and partly isolated basin, is strongly influenced by glacial freshwater inlfow, bringing significant amount of mineral suspension. Its mean annual content amounted up to 46 mg dm-3. Sea anemone (Edwardsia sp.), bivalves (Yoldia eightsi, Laternula elliptica and Mysella sp.), amphipods (mostly Cheirimedon femoratus) a well as some species of polychaetes constituted almost 95% of zoobenthos biomass and 90% of abundance. Four different assemblages of benthic invertebrates, with total biomass ranging from 0.002 kg m-2 up to 1.7 kg m-2, were distinguished in this relatively small (about 12 ha) area. It seems that the freshwater impact influences the composition of an assemblage occurring close to the edge of a glacier. Relatively rich crustacean fauna was encountered in the shallow part of the cove near its entrance. Almost complete lack of echinoderms in Herve Cove, that are common in the shallow Antarctic sublittoral, should also be noted. Macrozooplankton of Herve Cove was dominated by Copepoda. The most frequent and abundant species were: Oithona similis, Ctenocalanus citer and Metridia gerlachei. Far less numerous Chaetognatha represented by three species, Ostracoda, Polychaeta, Pteropoda and Siphonophora constituted only 2.5% of all planktonie animals collected.
The pinnipeds were counted on the western shore of Admiralty Bay during 1994. It was found that the numbers of one breeding species Mirounga leonina is stable, the remaining four species show a variable pattern of occurrence. However, there is no evidence to detect any trend since 1988.
Grain refining and modification are common foundry practice for improving properties of cast Al-Si alloys. In general, these types of treatments provide better fluidity, decreased porosity, higher yield strength and ductility. However, in practice, there are still some discrepancies on the reproducibility of the results from grain refining and effect of the refiner’s additions. Several factors include the fading effect of grain refinement and modifiers, inhomogeneous dendritic structure and non-uniform eutectic modification. In this study, standard ALCAN test was used by considering Taguchi’s experimental design techniques to evaluate grain refinement and modification efficiency. The effects of five casting parameters on the grain size have been investigated for A357 casting alloy. The results showed that the addition of the grain refiner was the most effective factor on the grain size. It was found that holding time, casting temperature, alloy type and modification with Sr were less effective over grain refinement.
The aim of the current study was to examine the structure of an alloy treated at various temperatures up to 2,000–2,100 °C. Among research techniques for studying alloy structure there were the electron and optical microstructure, X-ray structure, and spectral analysis, and for studying the developed furnace geometric parameters the authors employed mathematical modeling method. The research was performed using aluminum smelting gas-fired furnaces and electric arc furnaces. The objects of the study were aluminum alloys of the brand AK7p and AK6, as well as hydrogen and aluminum oxide in the melt. For determining the hydrogen content in the aluminum alloy, the vacuum extraction method was selected. Authors have established that treatment of molten aluminum alloy in contact with carbon melt at high temperatures of 2,000–2,100 °C has resulted in facilitating reduction of hydrogen and aluminum oxide content in the melt by 40-43% and 50-58%, respectively, which is important because hydrogen and aluminum oxide adversely affect the structure and properties of the alloy. Such treatment contributes to the formation of the extremely fine-grained microstructure of aluminum alloy.