Meso- and macrozooplankton communities in the Weddell Sea, Antarctica

The present paper describes composition and abundance of meso- and macrozooplankton in the epipelagic zone of the Weddell Sea and gives a systematic review of encountered species regarding results of earlier expeditions. Material was sampled from 6 February to 10 March 1983 from RV Polarstern with a RMT 1+8 m (320 and 4500 μm mesh size). In agreement with topography and water mass distribution three distinct communities were defined, clearly separated by cluster analysis: The Southern Shelf Community has lowest abundances (approx. 9000 ind./1000 m3). Euphausia crystallorophias and Metridia gerlachei are predominating. Compared with the low overall abundance the number of regularly occurring species is high (55) due to many neritic forms. Herbivores and omnivores are dominating (58% and 35%). The North-eastern Shelf Community has highest abundances (about 31 000 ind./1000 m3). It is predominated by copepodites I–III of Calanus propinquus and Calanoides acutus (61%). The faunal composition is characterized by both oceanic and neritic species (64). Fine-filter feeders are prevailing (65%). The Oceanic Community has a mean abundance of approximately 23 000 ind./1000 m3, consisting of 61 species. Dominances are not as pronounced as in the shelf communities. Apart from abundant species like Calanus propinquus, Calanoides acutus, Metridia gerlachei, Oithona spp. and Oncaea spp. many typical inhabitants of the Eastwind Drift are encountered. All feeding types have about the same importance in the Oceanic Community

The relationship between the distribution of plankton biomass and plankton communities in the Drake Passage and the Bransfield Strait (BIOMASS-FIBEX, February-March 1981)

In the investigated area of ca. 79 thousand (miles)^2,krill biomass, as designated by Data Workshop 1981 in Hamburg, makes up about 17% of zooplankton wet weight in the surface 100m water layer. Based on our own hydroacoustic measurements over an area of 48 thousand (miles)^2,krill biomass there makes up about 44% of the total zooplankton biomass. Three plankton communities with distinct trophic relations and the dominance of certain taxa have been distinguished in the area investigated. The "continental" community comprises phytoplankton with large quantities of flagellata, small phytoplankton consumers, predatory Cyclopoida, krill, carnivorous Parathemisto, and also larvae and young Channichthyidae. The "antarctic" community contains planktonic diatoms, Radiolaria, phytophagous Calanoida, Pteropoda and carnivorous Chaetognatha. The "intermediate" community is completed by Appendicularia, naupli, krill larvae, predacious Polychaeta and immature Nototheniidae. The distribution of plankton communities and plankton biomass in the research area may provide biological indicators for the intensity of water inflow from the Weddell Sea

Geostrophic currents in the South Shetland Islands area during FIBEX

Based on the Polish/West German FIBEX (First International BIOMASS Experiment) oceanographic data set a description of the kinematic situation in the South Shetland Islands area during February/March 1981 is given. By means of the dynamic topography the distribution of water masses originating from the Bellingshausen Sea and the Weddell Sea, as well as their temporal and spatial changes are discussed

Cryoconite holes and cryocavernes on fast ice in Antarctica

Kriokonity są cylindrycznymi otworami powstałymi w wyniku topnienia na lodowcu w otoczeniu ziarn mineralnych. Takie formy obserwowano na powierzchni przylepy lodowej powstałej na morzu w sąsiedztwie oazy Thala Hills na Ziemi Enderby w Antarktydzie Wschodniej. Otwory kriokonitów są większe przy brzegu niż dalej od brzegu w wyniku selekcji cząstek mineralnych wynoszonych przez wiatr z oazy. W przylepie lodowej powstają też kriojamy jako efekt topnienia lodu wokół fragmentów makroglonów, które przylgnęły do dna powstającego lodu, często wraz z lodem dennym. Kriojamy i kriokonity są więc różnego pochodzenia. Prezentowane są warunki środowiskowe i tworzenie się zespołu podlodowego.Cryoconite are cylindrical melt holes on glacial surface. Such creature were observed on surface of landfast sea ice near Thala Hills oasis in Antarctic. Holes are larger near shore than off shore depend of size of minerals selected by winds. In the land fast ice cryocavernes vere observed as effect of melting water around of macroalge attached bottom of ice. Cryocavernes are different orginate than cryoconites. Subfast ice community and environmental changes are presented