Polish Polar Research

General meteorological conditions in the Admiralty Bay in 1978 did not deviate from those of many years. The data for 1978 were used to analyse the co-occurrence of four most perceptible meteorological parameters: temperature, air humidity, wind speed and precipitation. In summer these elements occurred simultaneously only in 1 — 2 intervals of values, in winter their occurrence within individual intervals was less numerous, but covered more of them.

On the basis of surface pressure analyses covering the area of south-west Atlantic, maps of monthly mean pressure fields for the period from March to December 1979 were drawn. In order to accentuate the dynamics of pressure processes, maps of standard deviation as well as of the skewness coefficient of the values forming the pressure field were also prepared. Apart from this, the variation of pressure in the particular points of the field in the months considered, was discussed. Attention was drawn to the distinct quasi-periodicity, dependent on location of the given point.

This study gives an analysis of the variation of main meteorological parameters on the Station Arctowski in the time from December 1979 through March 1980 — the summer season of the IV Antarctic Expedition of the Polish Academy of Sciences. Characteristics of wind speed and direction, of air temperature, atmospheric pressure, precipitation, cloudiness, soil temperature at the station and surface water temperatures of the Admiralty Bay are based on the standard synoptic observations.

Studies conducted between December 20. 1978 and February 20. 1979 on Arctowski Station show that daily sums of total radiation ranged from 165.5 to 834.5 mWhr x cm2. Maximal mean hourly radiations were recorded from 12 to 14 hours (39.7—72.4 mWhr x cm2).

In the austral summer of 1977/78 phytoplankton populations in Ezcurra Inlet, Admiralty Bay, reached maximum abundance at the end of February; two smaller peaks of growth occurred in January. Flagellates and "monads" were dominant in the plankton, except two days in December, when diatoms were prevalent. Thalassiosira untarctica and a few species of the genera Nilzschia and Chaeloceros were the major diatoms during the summer. Several other diatoms. Corethron criophilum. Eucampia bulaustium. and Rhizosolenia spp. together with the all-summer dominants, contributed to the diatom peak in December, following the breaking of ice. Algal peaks always followed periods of calm days and stable atmospheric pressure; the increased stability of the water column at such times appears to be the factor determining the onset of the periods of phytoplankton maxima. Decline of algal peaks could be largely attributed to grazing by Euphausia superba and E. crystallorophias.

The occurrence of 18 species of algae was stated in the investigated region. Among them the following were predominant: Himantothallus grandifolius, Desmarestia menziesii, Cystosphaera jacqninotii, Ascoseira mirabilis. Leptosomia simplex. Adenocystis utricularis. Monostroma hariotii, Iridaei: obovata, Hildenbrandia lecunnellieri, Plocamium coccineum and Phycodrys antarctica. Vertical stratification of the distribution of three singled out communities of algae was observed downwards to the depth of 90 m, which is the limit of the occurrence of the algae in the Bay. The process of decomposition depends on the place where it occurs, the kind of the thalluses and the season of the year. The quickest decomposition of algae was observed on the shore, in the summer and spring. The total quantity of algal matter washed ashore along 15.8 km of the coast line of Admiralty Bay, during the period between February and October 1979, was estimated at 279 metric tons of dry weight matter. From this quantity, in result of decomposition of the algae on the shore, 75 tons of the matter were released during an average time of 12 days. The remaining 204 tons of partially decomposed algal matter are driven by winds farther inshore or into the waters of the Bay or remain ashore among the stony rubble.

It appears from the analysis of the chemical composition of macroalgae of the Antarctic: Adenocystis utricularis and Himantothallus grandifolius (brown algae), Leptosomia simplex (red algae) and Monostroma hariotti (green algae) that the examined algae, brown algae in particular (mainly Adenocystis utricularis), are rich in mineral components, primarily: sodium, potassium, hologens, and structural polysaccharides. Organic substances, such as: proteins, amino acids, lipids, fatty acids, saccharides reduction, chlorophylls and carotenoids, occur in the analysed algae in quantities much smaller in comparison with taxonomically similar macroalgae derived from marine environment having more favourable hydrochemical and climatic conditions.

In 25 krill samples (Euphausia superba) collected at the Scotia Sea and in the area of South Georgia, South Orkney and South Sandwich Islands, Antarctic Peninsula and the eastern part of the Bellingshausen Sea the concentrations of Cd, Pb. Zn, F, 90Sr, 137Cs, U and 239, 240 Pu has been determined. The corresponding average concentrations were found to be: Cd — 2.5, Pb — 3.4, Z n — 123.1 , F — 50 (ppm dry weight), 90Sr— 1.9, 137Cs — 4.7 (mBq x -1 dry weight), U — 11.1 (ppb dry weight) and 239, 240Pu - 0.08 (mBq x g-1 dry weight).

Crude oil and light or heavy oils as well as the detergent ABS in concentrations of 5 and 50 ppm partially inactivate arylsulphatases in Euphausia superba and E. crystallorophias. After one hour exposure to detergent solutions the arylsulphatase activity in experimental animals transitorily increased. The arylsulphatase activity proved to be affected also in krill homogenates. The change of temperature, of the krill incubation in solution of crude oil or detergent, from — 1°С to + 1°C did not influence the enzyme activity. The damage of lysosomal membranes, by oils and the detergent, has been confirmed by the fact of enhanced penetration of Trypan blue into krill tissues.

Information is presented concerning amphipod crustaceans eaten by three penguin species breeding on King George Island: Pygoscelis adeliae, P. antarctica and P. papua. In their stomachs 10 gammaridean and 3 hyperiidean amphipod species were found. The most abundant species was Parathemisto gaudichaudii. Noteworthy are the records of recently described and still poorly known species: Eusirus propeperdentatus and Eusirus cf. tridentatus. Some 15% of all amphipod specimens found in penguin stomachs were benthic species that are very common in the Antarctic littoral and which probably swarm.

In the summer of 1977/78, materials for determining the age and growth rate of Pseudochaenichthys georgianus Norman, 1937 were obtained in the South Georgia region. The 11—51 cm long fishes were of the age 1+ to 13+. The curvilinear relationship between the body length and the otolith radius took an S shape. In the first four years annual increments are almost identical and start to decrease in the following years. Spawning may occur in the 5th or 6th year of life, and hatching of larvae from eggs laid in autumn (IV—VI) takes place at the end of winter (IX of X). Larvae and juvenile fish lead an exclusively pelagic life, while older fish feed in near-bottom layers: when resources are scare there they seek food in the pelagial.