The paper describes the communities of laminarians and their macrofauna at the western coasts of Spitsbergen. The following aspects are considered: specific composition of fauna, spatial distribution of animals within the algae, trophic structure of fauna associated with the laminarians. Some zoogeographic remarks are included.

The list of shallow—water molluscs: chitons (2 species), gastropods (33 species) and bivalves (36 species) of Isfjorden is presented. Distribution, frequency and domination structure are discussed and zoogeographical analysis is presented.

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.

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.

Between 1979 and 2007, various sampling projects from the Polish Arctowski Research Station in Admiralty Bay, King George Island, Antarctica, collected a diverse assemblage of pycnogonids, inter alia . Examination of this material has revealed 24 species in 11 genera and six families: all of this material is described. Samples were from poorly− sorted fine−sand to coarse−silt substrata, at depths between 27 and 405 m. The diverse assemblage was of species consistent with the known pycnogonid fauna of these depths in the South Shetlands and the Palmer Archipelago region, and includes a number of species re− corded for only the second time since the types. As typical for Antarctic waters, the predominant and most diverse genus was Nymphon (nine species); the prevalent species was Nymphon eltaninae , not Nymphon australe : implications for the apparent wide−distribution of records of the latter species are discussed. These records increase the biogeographical range of Nymphon subtile and Nymphon punctum from Subantarctic waters to the Scotia Sea

The eight most abundant species (mean density >20 ind. m −2 ), which occurred at high frequencies (mean >30%) were selected from grab samples in the three Svalbard fjords: Hornsund, van Mijenfjord, and Kongsfjord, in the summer seasons between 1997 and 2007. Six polychaete and two bivalve species comprised more than 47% of the individuals and the biomass in all the samples examined. Four species are cosmopolitan, while the others are widely distributed Arctic−boreal species, and none has Arctic origin. Their density, frequency of occurrence, and biology are very similar across the wide geographical range from boreal to Arctic conditions. As the diversity of benthic fauna in the fjords studied increases (from 172 to 238 species), the dominance of the eight species in the soft bottom community diminishes from 76% to 47%. In times of hydrological regime shift, i.e. , the warming of the European Arctic, it is unlikely that the abundancy of these species in the soft bottom fjordic ecosystems will change. The most common soft bottom species are not good indicators of environmental change in the Arctic, and rare, specialized species are better option for indicative purposes.

We used an artificial substratum (plexiglass tiles) to compare diatom communities at three different depths at two sites differing in their hydrological conditions and glacier melt-water influence. Samples at 1 m depth were taken during early summer in 2018, whereas samples at 3 m and 6.5 m were obtained in late summer 2020. The tiles were submerged for a period of up to 45 days in 2018, and up to 34 days in 2020. Water temperature, salinity, conductivity, oxygen saturation and concentrations, and Secchi depth were measured multiple times at both sites. During late summer of 2020 Photosynthetically Active Radiation (PAR) was also measured at depths of 3, 6.5 and 10 m at both sites. The communities constituted of a total of 50 taxa. Colonization and community development followed the same scheme at both sites and at all depths, with an early establishment of the dominant taxa, and a decline in species richness, diversity, and evenness indices over the time towards relatively stable low values. Based on the results of PERMANOVA, ANOSIM and SIMPER analyses, diatom communities were site-specific, with 49% dissimilarity between the sites. Mechanical disturbances, such as wave action and ice scouring, as well as depth (and light availability) seemed to be the main factors driving the differences. The motile Navicula aff. perminuta dominated under mechanical disturbances at various light conditions, Navicula glaciei preferred calm shallow waters, and erect diatom growth forms were present in higher numbers in deeper waters with deteriorated light conditions.

Field and laboratory protocols that originally led to the success of published studies have previously been only briefly laid out in the methods sections of scientific publications. For the sake of repeatability, we regard the details of the methodology that allowed broad−range DNA studies on deep−sea isopods too valuable to be neglected. Here, a com− prehensive summary of protocols for the retrieval of the samples, fixation on board research vessels, PCR amplification and cycle sequencing of altogether six loci (three mitochondrial and three nuclear) is provided. These were adapted from previous protocols and developed especially for asellote Isopoda from deep−sea samples but have been successfully used in some other peracarids as well. In total, about 2300 specimens of isopods, 100 amphipods and 300 tanaids were sequenced mainly for COI and 16S and partly for the other markers. Although we did not set up an experimental design, we were able to analyze amplification and sequencing success of different methods on 16S and compare success rates for COI and 16S. The primer pair 16S SF/SR was generally reliable and led to better results than universal primers in all studied Janiroidea, except Munnopsidae and Dendrotionidae. The widely applied universal primers for the barcoding region of COI are problematic to use in deep−sea isopods with a success rate of 45–79% varying with family. To improve this, we recommend the development of taxon−specific primers.

In the Admiralty Bay 36 taxa of macroalgae were found. Among them the most common were: green alga Monostroma hariotti, red algae — Georgiella confluens, Iridaea cordata, Leptosarca simplex and Plocamium cartilagineum, and brown algae — Adenocystis utricularis, Ascoseira mirabilis, Desmarestia anceps, D. ligulata, D. menziesii and Himatothallus grandifolius. The bottom surface covered with macroalgae (in the orthogonal projection on the water mirror) amounts to 36,9 km2 i.e. 31% of the total surface of the bay. In the central part of the Admiralty Bay the macroalgae aggregations occupy 35% of the bottom surface and are most abundant in respect to the density, biomass, number of taxa (33) and diversity. There were distinguished 3 zones of vertical distribution of phytobenthos in the Admiralty Bay. I zone includes the macroalgae in epilittoral, littoral and sublittoral to the depth of 10 m. II and III zones are situated in sublittoral within the depths of 10 60 m and 60—90 m, respectively. Each zone is characterized by the occurrence of different aggregation of taxa. The bottom areas belong to I, II and III zone of macroalgae make 28%, 64% and 8% respectively in relation to the total surface of phytobenthos in the bay. Vertical range of the distinguished zones varies in different parts of the Bay in relation to the bottom character. Macroalgae occur down to the depth of 90 —100 m. The composition of the macroalgae flora evidences for its transitory character between the benthic subantarctic flora and that of the areas adjacent to the Antarctic continent.

A collection of 15 283 individuals of tanaidacean crustaceans was gathered by successive Polish Antarctic Expeditions in the years 1977-1993 in Admiralty Bay (King George Island, South Shetland Islands). Twelve species belonging to three families are identified in this study. The material is clearly dominated by Nototanais antarcticus (Hodgson, 1902); other common species were Nototanais dimorphus (Beddard, 1886) and Peraeospinosus sp. A. The highest density of tanaids was over 140 000 specimens m-2 , occuring on a muddy bottom in Herve Cove lagoon.

In 1920 qualitative and quantitative benthos samples collected in Barents Sea sublittoral in the years 1951-1983 154 species, 77 genera and 30 families of Amphipoda Gammaridea were identified. Species diversity was highest among the Lysianassidae, Oedicerotidae, Ampcliscidae, Calliopiidae and Pleustidae. Ampelisca eschrichti clearly dominated the material. This same species, plus Haploops setosa and Anonyx nugax were both the most frequently occurring and most numerous species. The distribution of amphipods in the Barents Sea sublittoral varies both in diversity and numbers by region, depth, sediments and water temperature. Zoogeographical changes are discussed in the present paper. Altogether 331 species of amphipods have been hitherto collected in the Barents Sea, of which 317 species, 126 genera and 39 families belong to the suborder Gammaridea.

Main aim of the study was to search for possible differences in diatom colonization and their communities under the influence of glacier meltwater inflow and when unaffected by glacier meltwater, and also to define the time needed for the development of diatom communities on newly submerged substrates at small depths in Antarctica. We used artificial substrates (Plexiglass© tiles), submerged at a depth of 1 m below the sea surface at two locations at the South Bay of Livingston Island: (1) Johnsons Dock – a cove, known to receive glacier meltwater with sediments, and (2) outside the cove, generally unaffected by glacial meltwater. Samples from the natural epilithon at similar depth were also taken as a reference for diatom community structure. Statistical testing the differences between the two sites was not possible this time, but the samples allowed us to compare the sites in terms of diatom growth, species richness, diversity and evenness changes in diatom communities along the time of the experiment at both sites and with the natural epilithon at similar depths. Diatom colonization followed the three-phases scheme (colonization, logarithmic growth and equilibrium) as in other latitudes. Based on the valve density and community indices e.g. species richness, diversity (1-D) and evenness (J’), we consider that at least three weeks might be necessary to obtain sufficiently representative for the environment diatom communities on new substrates at small depths in Antarctica, in conditions similar to those of South Bay. No particular differences between the sites were noted in the colonization scheme, but the diversity (1-D) and evenness (J’) were higher at glacier influenced site, as well as the number of the valves on the substrates. Sea ice diatoms prevailed at the glacier influenced site. We suggest that species exchange between the sea ice and other hard substrates do exist, at least for some taxa, and such species might be indicative for variations in both salinity and water transparency, related to glacial meltwater inflow.

226 taxa (180 identified to species) of benthic invertebrates are recorded from Admiralty Bay on the basis of the material collected by Polish Antarctic Expeditions. Main groups concerned are Folychaeta, Mollusca, Amphipoda and Echinodermata. For each species the bathymetric range, the frequency, the abundance and the geographical distribution are given.

Considering the fact that water quality monitoring programs in Poland are mostly based on physicochemical variables and saprobie systems, it is important to evaluate also the possibility of applying biotic index methods for water quality assessment. The investigation was carried out at the Ścinawa Niemodlińska river (Opole Voivodeship). Benthic macroinvertebrates from seven sampling sites were sampled twice in 1999. Belgian Biotic Index values were calculated on the basis of the results of qualitative and quantitative analyses of the macroinvertebrate community, as the example of the biotic index application. BBi values indicated a low, but different in particular sites, pollution level of the studied ecosystem.