Polish Polar Research

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.

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.

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.

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.

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.

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.