Wyniki wyszukiwania

Filtruj wyniki

  • Czasopisma
  • Data

Wyniki wyszukiwania

Wyników: 48
Wyników na stronie: 25 50 75
Sortuj wg:

Abstrakt

The results of several years of studies concerning the role of penguin rookeries in the functioning of the land ecosystems in the maritime Antarctic are summarized. The origins of phosphatic ornithogenic soil in the areas of currently active penguin rookeries arc presented. In the maritime Antarctic occurs relatively fast microbiological decomposition and mineralization of large amounts of excrements carried into coastal area by penguins during breeding period. Chemically aggressive water solutions of guano react with underlaying rocks. This process brings about the occurrence of wide zones of phosphatization. These processes cause the appearance of the series of phosphate minerals whose composition and properties depend on the changing physical and chemical conditions of the soil environment. It has been discovered that in the rookeries for various reasons abandoned by penguins phosphates are still present in large amounts and, gradually changed and washed out, have been for hundreds, or even thousands years a source of nutrients for plants growing in poor Antarctic land ecosystems. These soils came to be called the relic ornithogenic soils of the maritime Antarctic. The stages of plant colonization in the abandoned penguin rookeries were traced. The differences in the fate of the organic matter carried out from the sea to the coastal area by sea-birds in various climatic zones were discussed.
Przejdź do artykułu
Słowa kluczowe Antarctic monitoring birds mammals

Abstrakt

In the breeding season 1988/89, within the region of SSSI No. 8, nesting of 12 species of birds was observed. The highest number of nests — 24430 — belonged to three species of pygoscelid penguins; 77.1% were the Adelie penguin. Relatively high fluctuations in the number of penguins in some rookeries in particular breeding seasons were confirmed. During regular countings of mammals' in 1988 the presence of 5 species of Pinnipedia was noted, of which the southern elephant seal was most numerous in the summer season, whereas crabeater seal — in winter. In the region of SSSI No. 8, breeding of southern elephant seal and Weddell seal was observed. Fluctuations in the number of seals in this region in the period 1977—1988 were insignificant.
Przejdź do artykułu

Abstrakt

A total of 704 fishes representing 39 species were examined. Twenty five digenean species were recognized. Only one species previously found by the present author in a fiord of this area was absent in the material. Pelagic species were usually not parasitized by digeneans, while demersal fishes were normally found to be infected. Results of the present study are compared to those from fiords. Seven species were found to be widely distributed. Two of them, Macvicaria pennelli and Genolinea bowersi, were associated with an inshore fiord environment and could be used as biological tags indicating the association of hosts with this kind of environment. Three of widely distributed species, Lepidapedon garrardi, Elytrophalloides oatesi and Lecilhaster macrocotyle, were not clearly associated with any environment. Gonocerca phycidis, Neolebouria antarctica and other less widely distributed species, with the exception of Postmonorchis variabilis, were associated with deep part of fiords and/or open sea shelf environment. The level of infection of open sea fish at the South Shetlands was low. Many fish species living at South Georgia were massively infected; the dominant species in this area is E. oatesi, which was rare off the South Shetland Islands. A total of 45 digenean species occurring in the Antarctic fish were listed. Eleven of them were not endemic.
Przejdź do artykułu
Słowa kluczowe Antarctica krill lipids

Abstrakt

Using a thin layer chromatography the content and composition of krill lipids was examined in different sex and maturity stages. The content of lipids decreased in the following sequence: immature males — females with eggs — juvenile specimens — spent females — mature males. In females the differences concerned mainly phospholipids and waxes, in males — triacylglicerols; this fact proves the different utilisation of lipids for reproduction in both sexes.
Przejdź do artykułu
Słowa kluczowe Antarctica Crustacea krill lipids

Abstrakt

A composition of lipids of some Antarctic Crustacea (Euphausia superba. E. triacantha. Thysanoessa macrura and Mysidacea gen. sp. indet.) caught in the Admiralty Bay (South Shetlands) was compared. Lipids of E. superba differed in low content of waxes that evidences for different management of lipids than in other examined Crustacea.
Przejdź do artykułu
Słowa kluczowe Antarctic krill lipids

Abstrakt

The photo-oxidability of lipids taken from 32 samples of krill from different dates of catch has been examined for photooxidation. Relations were indicated between the rate of accumulation of peroxides in the process of lipids, exposure and content of lipids in krill, its iodine value and amount number of carotenoids.
Przejdź do artykułu

Abstrakt

Quaternary sediments in the southwestern Nordenskiöld Land are described with particular emphasis put on distribution of erratics against their basset matrices. Results confirm previous suppositions on directions of past glacial advances from east westwards. The latter separated by sea submergences, caused translocations of the rock material. This process was most intensive in upstreams of large mountain valleys.
Przejdź do artykułu

Abstrakt

Basing of fieldworks geomorphologic and geologic setting of 14 raised marine beaches in northern Hornsund Region was presented. Their age is approximated by radiocarbon and thermoluminescence datings of sediments. The latter indicated that the four highest but mostly questionable marine beaches (220—230,200—205,180—190 and 100—120 m a.s.l.) should be referred to the Wedel Jarlsberg Land (Saalian) Glaciation. The four lower beaches (80—95, 70—75, 50—60 and 40—46 m a.s.1.) are connected with the Bogstranda (Eemian) Interglacial and the pre-maximum part of the Sorkapp Land (Vistulian) Glaciation. The post-maximum part of this glaciation, including Lisbetdalen Stage (50—40 ka) and Slaklidalen Stage (30—20 ka), was the time when the three still lower marine beaches (32—35, 22—25,16—18 m a.s.l.) were formed. Three lowermost marine beaches (8—12,4.5—6,2 m a.s.l.) are of the Holocene age.
Przejdź do artykułu

Abstrakt

We propose contents of topographic maps for polar areas to be supplemented with such landforms that are easily identified during the analysis of air or terrestial photographs. Such landforms include rock outliers (monadnocks), glacial boundaries, a beach and thick mantles of tundra vegetation. All these landforms create together with fluvial and lake patterns a system of elements that enable location of users and therefore make preparation of other (e.g. geological, geomorphological or glaciological) maps possible.
Przejdź do artykułu

Abstrakt

Geological investigations of the 4th Polish Geodynamic Expedition to West Antarctica, summer 1990/91, covered the following topics: volcanological studies and mapping at Deception Island; stratigraphic, palaeonotological and sedimentological studies, and mapping of Tertiary glacial and glacio-marine strata on King George Island; sedimentological and mesostructural studies, and mapping at Hurd Peninsula, Livingston Island; and palaeontological sampling of Jurassic (Mount Flora Formation) and Trinity Peninsula Group deposits at Hope Bay, Trinity Peninsula.
Przejdź do artykułu
Słowa kluczowe Arctic Spitsbergen archeology

Abstrakt

The author makes a review of conceptions explaining the beginnings of human penetration into the region of Spitsbergen and points to attempts of employing archeological data in this task. In his analysis of the development, the tendencies and the state of the excavatory exploration of Spitsbergen the author tries to define the cognitive capabilities of archeology in the investigation of the history of human activity in the area. The appraisal of achievements in the field prompts the author to propose new priorities in the research problems hitherto undertaken by archeologists. Greater emphasis should be put on the examination of the structure and the dynamics of the analysed processes, rather than on the purely historical (event-centered) aspects.
Przejdź do artykułu
Słowa kluczowe Arctic Spitsbergen macromycetes

Abstrakt

This paper reports the species of macromycetes collected on NW Sörkapp Land, Spitsbergen: all the species are new to the area. Brief notes on taxonomy, ecology and distribution of the species are provided.
Przejdź do artykułu

Abstrakt

In the Fugleberget catchment area (Spitsbergen, Hornsund Fiord region) the growing season lasted 95 days, with growth beginning under the snow. In this time shoots of moss Calliergon stramineum reached a mean length of 19 mm and mean biomass of 0.593 mg dry weight. Annual primary production of moss communities amounts to 220-270 g dry weight per square meter per year. In the first year of destruction the dead plant material lost 30-45% of its initial value, after 10 years only ca 25% of the initial amount of organic matter was left.
Przejdź do artykułu
Słowa kluczowe Arctic Svalbard benthos

Abstrakt

The infauna of the soft bottom of Nottinghambukta was studied quantitatively. The distribution of 5 most abundant species: Liocyma fluctuosa (Bivalvia), Dendrodoa grossularia (Ascidiacea), Priapulus caudatus and Halicryptus spinulosus (Priapulida) and Chone duneri (Polychaeta), in this Arctic estuary has been presented.
Przejdź do artykułu

Abstrakt

Two West Spitsbergen fiords, Hornsund (77°N) and Kongsfjorden (79°N) were compared with respect to their hydrology and zooplankton occurrence on the base of two summer surveys made in 1987 and 1988. Both fiords were found to be influenced by four types of masses: Atlantic Waters, Intermediate Atlantic Waters, Local Waters and Brackish Surface Waters, Intermediate Atlantic Waters, Local Waters and Brackish Surface Waters. The amount of fresh water in both fiords reached up to 10% of water volume of the uppermost water layers. Hornsund in August 1987 was richer in mesozooplankton biomass than Kongsfjorden in 1988. Estimated energie value of pelagic prey of marine birds was 180-500 KJ/100 m3 in Hornsund, and 130-200 in Kongsfjorden. Two major plankton communities were found in both fiords: Pseudocalanus community in the inner fiord basins and Calanus dominated community in the outer areas of the fiords. Plankton occurrence in fiords was not linked directly with the temperature — salinity patterns but rather with dynamic phenomena like upwellings and wind drift of surface waters.
Przejdź do artykułu

Abstrakt

The paper presents a list of over 100 amphipod taxa hitherto recorded in the Admiralty Bay, South Shetlands (Tab. 1). In Tab. 2 the distributional patterns of Amphipoda in upper and middle sublittoral (depth 5-150 m) of the Admiralty Bay are given. Notes on the taxonomy of some taxa are presented.
Przejdź do artykułu

Abstrakt

Four water masses were distinguished in the upper water layer between Elephant Island and the South Orkneys. Measurements of temperature, salinity, concentrations of dissolved oxygen and silicates were used for the analysis of the hydrological situation and to recognise the origin of water masses. For additional information, nitrates and chlorophyll concentrations were used. Drake Passage and Bransfield Strait waters occupied the western part of the investigated area, from surface to 150 m depth. Below, the Circumpolar Warm Deep Waters (CWDW) were found. The region east of 53.5°W was occupied by winter Weddell Sea water. Above this, a 45 m thin layer of summer modification of Weddell Sea Surface Water was found between 49°W and the South Orkneys. The highestchlorophyll α concentrations were found in this modified water.
Przejdź do artykułu

Ta strona wykorzystuje pliki 'cookies'. Więcej informacji