The paper deals with Recent and relic phosphatic soils of ornithogenic origin which occur in ice free oasis of the maritime Antarctic Zone (Antarctic Peninsula and King George Island regions). These soils form on rocky and clay weathering covers within and around of penguin rookeries. Their morphology strongly depends on penological character of a substrate and climatic differentiation of a region. They are built of a surface layer of guano and underlying zone of a phosphatized rock. Except organic matter and unstable urates, the guano contains calcium phosphates (fluorapatite somtimes brushite) and magnesium-amonium phosphate (struvite). The phosphatized zone consists of phosphatic- silicate clays in which occur diversified aluminium-iron phosphates bearing potassium and ammonium ions (leucophosphite, minyulite, taranakite, amorphous aluminium phosphate). The guano layer is strongly reduced by erosion and weathering in ornithogenic relic soils left by penguins in areas abandoned by them during Holocene. Formation of a humus horizon of a plant origin may be observed under a vegetation cover in the relic soils. Clays of the phosphatized zone in these areas are transformed in the processes of chemical and mechanical weathering, by mass movements and frost processes.
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.
Communities of soil invertebrates were studied in 4 types of tundra ecosystems on Spitsbergen (Hornsund area) during the vegetative season of 1989. Taxonomic composition, density and biomass of soil fauna were evaluated in the sites along a gradient of increase in the biogenic impact of bird colonies, i.e. in polygonal tundra, mossy/lichenous tundra, Calliergon stramineum moss association, and mossy associations near a colony of Little Auks (Alle die). Average total biomass of soil invertebrates increased in this site sequence from 1.1 to 25.0 g wet weight x m-2 (mainly due to collembolans and nematodes). Seasonal dynamics of all groups of soil meso- and macrofauna (Nematoda, Enchytraeidae, Aranei, Acarina, Collembola, Coleoptera, Diptera larvae) is presented and discussed.
A high content of fluorine was found in ornithogenic soils around penguin rookeries on King George Island. South Shetland Islands. Fluorine is inherent in 0.11% in krill (Euphausia superba). eaten by penguins. Fluorine content in penguins excreta increased approximately to 0.43%. and after decomposition and leaching to 1.03%. The concentration grew during mineralization of organic matter in guano (up to 2.2%). In a surface layer of guano fluorine occurred in apatite. A phosphatization was noted in a subsurface zone as the result of a reaction between guano leachates and weathered volcanic rocks. In the upper part of this zone near the large rookeries a fluorine occurred in minyulite (aluminium phosphate containing potassium and fluorine) and fluorine content here reached 3.5%. Sometimes fluorine was also bound with amorphous aluminium phosphate (up. to 2.0%). formed as a result of incongruently dissolving of minyulite in pure water.
There were tested microorganisms in differents soils at Admiralty Bay region. The physiological groups of microorganisms were restricted by the kind of organic matter. There were found in ornithogenic soils in higher number the following groups of microorganisms; proteolytic bacteria, uric acid and L-asparagine ammonifying bacteria, chitin degrading bacteria, lecithin degrading bacteria and calcium phosphate dissolving bacteria. The nitrifying bacteria were found in lower horizons of ornithogenic soils in higher number. The nitrogen fixing bacteria were found in mineral soils covered by plant associations, only. The spore-forming bacteria were detected in ornithogenic soils and in soil influenced by man.