Necrophagous invertebrates of the Admiralty Bay of King George Island (South Shetland Islands, Antarctica)

Paper received 15 June 1985.In 1977 and 1980 rich materials of necrophagous invertebrates were collected in the Admiralty Bay of King George Island. The collecting was carried out in 9 stations differing with respect to their habitat conditions. The stations were established at depths ranging from 5 to 90 m. In baited traps placed in the stations 295074 specimens of various animals belonging to almost 100 taxa were caught. It was found that 23 species out of the above mentioned taxa were necrophagous, and 10 further species were suspected of necrophagy. On the basis of their specific composition and domination structure the summer and winter assemblages of necrophagous invertebrates were described and compared with each other. An analysis of spatial and seasonal changes in the structure and abundance of these assemblages was carried out. and the habitat preferences of particular species as well as a list of species displaying permanent or seasonal necrophagy were determinted. Three forms of the competitive community of necrophagous invertebrates were distinguished.The present investigations were supported by the Polish Academy of Sciences as a part of the Projects MR —II I6A and MR I 29A, and they were carried out during the I-st (I976-78) and IV—th (1979—80) Polish Antarctic Expeditions to the "Arctowski" Station

Profiling of Phenolic Compounds and Antioxidant Activity of Dry Extracts from the Selected Sorbus Species

The antioxidant efficiency of dry extracts from inflorescences and/or leaves of seven Sorbus species was studied using four in vitro tests of SET (single electron transfer) and HAT-type (hydrogen atom transfer) mechanisms. The 70% methanol extracts and its diethyl ether, ethyl acetate, n-butanol and water fractions were tested in parallel with the phenolic standards, e.g., caffeic acid, quercetin, BHA, BHT, and TroloxÒ. The SET-type activity of the extracts depended primarily on the extraction solvent. The most valuable extracts were n-butanol and ethyl acetate ones, which activity was high in the DPPH (EC50 = 3.2–5.2 μg/mL), TEAC (2.8–4.0 mmol Trolox®/g), and FRAP (9.8–13.7 mmol Fe2+/g) tests, and strongly correlated with the total phenolic levels (39.6–58.2% of gallic acid equivalents). The HPLC-PDA analysis of the extracts led to the identification of chlorogenic acid, isoquercitrin, hyperoside, rutin, quercetin 3-O-sophoroside, and sexangularetin 3-O-b-D-glucopyranoside as the main components. Apart from flavonoids and hydroxycinnamic acids, proanthocyanidins have also a significant impact on the SET-type activity. The HAT-reactivity of the extracts in the linoleic acid peroxidation test (IC50 = 36.9–228.3 μg/mL) depended more strongly on the plant tissue than on the extraction solvent, and its correlation with the phenolic content was weak. Both SET and HAT-type activity of the most potent Sorbus extracts was comparable with the activity of the standards, indicating their great potential as effective sources for health products

Structure of bryozoan communities in an Antarctic glacial fjord (Admiralty Bay, South Shetlands)

Bryozoans are among the most important groups of the Southern Ocean benthic macrofauna, both in terms of species richness and abundance. However, there is a considerable lack of ecological research focused on their distribution patterns and species richness on smaller scale, especially in the soft bottom habitats of Antarctic glacial fjords. The aim of this study was to describe those patterns in the Admiralty Bay. Forty-nine Van Veen grab samples were collected at the depth range from 15 to 265 m, in the summer season of 1979/1980, at three sites distributed along the main axis of the fjord. Among 53 identified species of bryozoans, 32 were recorded in the Admiralty Bay for the first time. The most common and abundant species were Himantozoum antarcticum, Inversiula nutrix and Nematoflustra flagellata. Genera such as Arachnopusia, Cellarinella and Osthimosia were the most speciose taxa. It was demonstrated that depth was important for the distribution of the bryozoans. More than half of the recorded species were found only below 70 m. An influence of glacial disturbance was reflected in the dominance structure of colony growth-forms. The inner region of the fjord was dominated almost entirely by encrusting species, while the diversity of bryozoan growth-forms in less disturbed areas was much higher. In those sites the highest percentage of branched, tuft like species represented by buguliform and flustriform zoaria was observed.The study was supported by a grant of Polish Ministry of Science and Higher Education No. 51/N-IPY/2007/0 as well as Census of Antarctic Marine Life Project. Krzysztof Pabis was also partially supported by University of Lodz internal funds. This research was also supported by the Polish Geological Institute-National Research Institute during the realization of the project numbered 40.2900.0903.18.0 titled “Bryozoan assemblage of Admiralty Bay—richness, diversity and abundance.” Urszula Hara is deeply grateful to Leszek Giro (Micro-area Analyses Laboratory at the Polish Geological Institute-National Research Institute, Warsaw), for providing SEM assistance during the project. We also want to thank two anonymous reviewers for their suggestions that helped us improve this article. Thanks are also due to Magdalena Błażewicz-Paszkowycz for language correction and polishing the final version of the manuscript