Jacek Siciński

Abundance and Biomass Estimates of the Benthic Fauna in Admiralty Bay, King George Island, South Shetland Islands

SummaryQuantitative benthic samples were collected along three transects in Admiralty Bay, King George Island, South Shetlands. At each of a total of 18 stations, between 15 and 250 m depth, we took 3 replicate samples with a van Veen grab. Animals collected were classed into major groups. Abundance and biomass per m2 was calculated for each sampling site. Considerable population densities and high biomass values were found. Most abundant groups were Bivalvia, Polychaeta and Amphipoda, whereas the largest part of the biomass was due to Ascidiacea, Ophiuroidea, Echinoidea, Polychaeta and Bivalvia. The maximum abundance recorded was 36,000 ind m-2 while the average was approximately 6500 ind m-2. Maximum biomass was over 2400 g m-2 with an average of ca. 700 g m-2. The contribution to the total biomass by groups such as the Oligochaeta, Cumacea and Tanaidacea was higher in the inner shallow part of Admiralty Bay (Ezcurra Inlet) than in the deeper areas of the bay. Our results confirm the reports on an unusually high density and biomass of the Antarctic sublittoral benthic fauna. Sessile suspension feeders belonging to the Bivalvia, Ascidiacea, sedentary Polychaeta, and vagile scavengers of the Ophiuroidea, Amphipoda and errant Polychaeta are the most significant groups in the Antarctic Ecosystem. The total benthic biomass in Admiralty Bay, based on the present preliminary quantitative data, was estimated to be over 600,000 t. This value is probably still an underestimate.

Amphipod crustaceans as an important component of zoobenthos of the shallow Antarctic sublittoral

Benthic quantitative samples were taken in 1988 in the soft bottom sublittoral of Admiralty Bay (King George Island, South Shetlands) using a Tvärminne-type bottom sampler and SCUBA-diving technique at 7 successive stations situated at depths from 4 to 30 m.Dominant animal groups in terms of abundance were Amphipoda, Polychaeta and Bivalvia, whereas in terms of biomass Echinoidea were also dominant. Amphipod crustaceans clearly dominated the zoobenthos at depths from 10 to 25 m (the numerical share surpaising 60%) with maximal abundance of abt. 17 000 ind m−2; in terms of biomass at specific depths amphipods occupied the 1st, 2nd or 3rd place with maximal biomass of abt. 100 g m−2 where the maximal total biomass of zoobenthos reached 260 g m−2 (10 m).Amphipoda were the most diversified group with some 35 taxa belonging to 14 families. Most species belonged to Eusiridae s.l. and Lysianassidae s.l. Dominant forms were Pontogeneiella brevicornis, Prostebbingia gracilis, Schraderia gracilis, Hippomedon kergueleni, Orchomenella cf. ultima, Cardenio paurodactylus and Paraphoxus rotundifrons.

Macrozoobenthos of two Antarctic glacial coves: a comparison with non-disturbed bottom areas

There are only few studies on shallow Antarctic benthic communities associated with habitats affected by intense mineral sedimentation inflow. The analysis of macrofaunal communities associated with two shallow, isolated glacial coves was performed in Admiralty Bay (King George Island) and compared with non-disturbed sites. Multivariate analyses (hierarchical classification, nMDS) clearly separated glacial cove communities (two assemblages) from the sites situated outside both basins (two assemblages). The community influenced by the streamflow of glacial discharge of meltwater situated in the area with sandy–clay–silt sediments had a very low species richness, diversity and abundance. It was dominated by eurytopic, motile deposit feeding polychaetes such as Mesospiomoorei, Tharyxcincinnatus and Leitoscoloploskerguelensis as well as the bivalve Yoldiaeightsi. The second glacial community of the area located at a grater distance from the outlet of the stream was characterized by sandy–clay–silt and clay–silt deposits and showed also a low diversity and species richness. The most abundant here were peracarid crustaceans, with the dominant opportunistic feeder Cheirimedonfemoratus. Community from the non-disturbed area with silty–clay–sand, and silty–sand sediments had higher species richness and diversity. The assemblage of fauna from the sandy bottom has values of those two indexes similar to those found in the disturbed areas.

Polychaetes of the shallow sublittoral of Admiralty Bay, King George Island, South Shetland Islands

Twenty five species of Polychaeta were recorded in soft bottom samples collected from 4-30 m. Total abundance of polychaetes ranged from 60 to 3300 m −2 . High abundance values were locally recorded for Microspio moorei, Tharyx epitoca and Ophelina syringopyge. These species, together with more regularly distributed Capitella capitata and Scolophos marginatus, constituted over 70% of all specimens. Total biomass value of the polychaetes varied between 3.8 and 46.4 g m −2 . Travisia kerguelenensis and Aglaophamus ornatus constituted over 75 % of total biomass. Species composition, richness and diversity of the polychaete assemblage varied with depth. Two parts of the investigated bottom section, differing in the polychaete assemblages structure, were distinguished; the first one in the depth range from 4-20 m and the second one at the depths of 25-30 m

Biogeographical affinities of polychaetes from Îles Crozet

The study of polychaetes from the Marion Dufresne expedition to the Îles Crozet in 1982 provided 45 species from depths ranging from 50–1055 m. The most abundant was Eunice pennata, found at all depths and in all types of substratum in about 66% of the samples. This species with Laetmonice producta, Harmothoe spinosa and Lanice marionensis made up over 50% of all polychaete specimens. A homogenous polychaete assemblage dominated by the above mentioned group of species was encountered in the shallower stations (100–300 m). A mosaic-like and less abundant polychaete fauna with some characteristic, abundant species: Amage sculpta, Laetmonice wyvillei, Leanira quatrefagesi and Melinna cristata was encountered in the deeper stations (300–1055 m). Clear similarities between the polychaete fauna of Îles Crozet and soft-sediment polychaete assemblages of Marion and Prince Edward Islands were noticed. No such affinity was encountered with the polychaete fauna of Îles Kerguelen. Their position in relation to the Polar Front as well as possible differences in bottom deposits (calcareous versus siliceous) may in part explain these dissimilarities. The biogeographical status of Kerguelen Islands is also discussed.

New data on the rare species Pseudodiamesa nivosa (Goetghebuer) (Diptera, Chironomidae)

Pseudodiamesa nivosa a species commonly regarded as a boreo‐alpine one, has been recorded at an altitude of 345 m a.s.l., in the source section of the Pilica River (Cracow‐Czestochowa Upland, Poland) and in one of the vaucluse springs in the Roztocze Region (230 m a.s.l.). It seems that the newly recorded P. nivosa populations might be regarded as a glacial relict connected with the periglacial zone.

Antarctic and Sub-Antarctic Asteroidea database

Abstract The present dataset is a compilation of georeferenced occurrences of asteroids (Echinodermata: Asteroidea) in the Southern Ocean. Occurrence data south of 45°S latitude were mined from various sources together with information regarding the taxonomy, the sampling source and sampling sites when available. Records from 1872 to 2016 were thoroughly checked to ensure the quality of a dataset that reaches a total of 13,840 occurrences from 4,580 unique sampling events. Information regarding the reproductive strategy (brooders vs. broadcasters) of 63 species is also made available. This dataset represents the most exhaustive occurrence database on Antarctic and Sub-Antarctic asteroids.

Biodiversity and biogeographic affiliation of Bryozoa from King George Island (Antarctica)

King George Island (KGI), which is located between the Antarctic and South American continents, may play a crucial role in the exchange of Bryozoa amongst the various Antarctic sectors and across the Polar Front. Knowledge regarding the biological diversity of this area could help us understand the evolution of the Antarctic ecosystem and its connectivity to the South American continent as well as the colonization ability of particular species. Here, we investigate the patterns of diversity and biogeographic affiliation of the cheilostome Bryozoa from KGI and the surrounding areas. Of 114 identified taxa from a depth range of 6–492 m, 26 species were reported for the first time in KGI. The most speciose genera were Camptoplites, Osthimosia, Smittina, and Cellarinella. Species richness at KGI consisted of 70% of the total bryozoans at the South Shetland Islands (SSI). Fifty-nine per cent of the bryozoans from KGI are endemic to Antarctica, which closely reflects the previously estimated endemism rate for bryozoans and other Antarctic taxa. Cluster analysis indicated that the strongest faunal links of SSI bryozoans were with Antarctic Peninsula assemblages, corresponding to the physical distance between both locations. The biogeographic similarities between SSI and South America confirm the broad trend of existing Antarctic–South American faunal links previously observed in bryozoans and many other taxa and indicate that SSI might be an important transitional zone between Antarctica and South America.