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The family Subergorgiidae comprises two genera, Subergorgia with three species and Annella with two species. All the previously known species are distributed in tropical and subtropical waters from the northern Red Sea to the central Pacific. The presence of a subergorgiid in Antarctic waters could support the hypothesis that at least part of the Antarctic fauna has its origin in the Cretaceous period, when Antarctica was part of the Gondwana continent. The new genus Rosgorgia with the new species inexspectata is placed in the family Subergorgiidae by the presence of smooth, fusiform and often anastomosing needles in the axis, wart spindles in the coenenchyme, and coelenteric cavities of polyps only present in the coenenchyme. The genus Rosgorgia differs from Subergorgia and Annella by the presence of tuberculate rods in the axis. It is further distinguished from Annella by the absence of double-disk sclerites in the coenenchyme, and not anastomosing branches. Accepted: 25 June 2000  相似文献   

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Sphaeralcyon weddellensis gen. nov. et sp. nov. is described and illustrated from three colonies collected in the eastern Weddell Sea on the Polarstern cruises ANT V/3 and ANT VI/3. The new genus is compared with three closely related alcyoniid genera, all having capitate or mushroom-shaped colonies and dimorphic polyps. Sphaeralcyon is readily distinguishable from Malacacanthus by the presence of sclerites (absent in the latter genus), and from Anthomastus by sclerite shape, mainly in the form of tuberculate spheroids, and by the horny periderm on the stalk (absent in Anthomastus). Sphaeralcyon also differs from Verseveldtia in the set of sclerites, which are elongate spiny rods and a different type of tuberculate spheroid, and in the presence of eight-points as anthocodial armature (absent in Verseveldtia). The discovery of this new genus lends further support to the notion that diversity in benthic communities in Antarctica is higher than suggested by previous studies. Accepted: 6 December 1999  相似文献   

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Twenty-seven species of benthic hydroids have been found in a small collection from off Bouvet Island (Antarctic Ocean). The material was obtained during the XXI/2 German Antarctic expedition with R.V. Polarstern 2003–2004. Of the 27 species collected, 21 were unknown from those waters. Consequently, the number of known species of benthic hydroids from the area has risen to 32, representing a high diversity location for this group in the Southern Ocean considering the sampling effort made. All species, including those previously known from Bouvet waters, are considered with respect to geographical distribution.The present work is an addition to the special issue “Macrobenthic studies at Bouvet island”, presenting work carried out from on board RV Polarstern in 2003/2004 and published in Polar Biology 29 (2006)  相似文献   

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A total of 61 species of hydroids, belonging to 13 families and 23 genera, were found during the Spanish Antarctic expedition Bentart 95 with the RV Hespérides. Ten of the species were identified only to generic level. The dominance of the subclass Leptothecatae, with 57 species, was remarkable. The remaining four species belong to the subclass Anthoathecatae. By far the most diverse family was the Sertulariidae, with 25 species (41%), followed by Haleciidae with nine species (15%) and Kirchenpaueriidae with six (10%). The family Plumulariidae, represented by one species of Nemertesia, is recorded for the first time from Antarctic waters. Eudendrium scotti, Perarella clavata and Symplectoscyphus hero are each recorded for the second time. Symplectoscyphus with 11 species was the dominant genus. Almost 60% of the species diversity is concentrated in just a little more than the 20% of genera. Nearly 70% of the species are endemic to Antarctic waters and 90% of them are restricted to Antarctic or Antarctic/sub-Antarctic waters.  相似文献   

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Summary Microplankton was sampled with a centrifugal suction pump in the surface layer (approx. 9 m) of the Bellingshausen Sea and the Bransfield Strait in March 1987, and concentrated with a 26m-mesh net. Bulk microplanktonic settling volumes were assessed, silicoflagellates and large thecate dinoflagellates were counted, and tintinnids were counted and identified to species. Average (and maximum) values for the entire area surveyed were as follows, settling volume: 6.7 (43.3) ml/m3; silicoflagellates: 674 (7777) ind./l, 0.57 (6.54) mg C/m3; dinoflagellates: 109 (1321) ind./l, 1.40 (16.98) mg C/m3; tintinnids: 52 (589) ind./l, 1.15 (9.87) mg C/m3. The three geographic zones defined objectively on the basis of tintinnid specific assemblages also differed sharply in their surface salinity, overall microplanktonic abundance and bulk settling volume. The Bransfield Strait, with lowest settling volume values (2.1 ml/m3) and cell concentrations, was characterized by the dominance of Cymatocylis affinis/convallaria. In waters around the tip of the Antarctic Peninsula microplanktonic settling volumes averaged 4.6 ml/m3, cell concentrations were intermediate, and 79% of the tintinnids were represented by Codonellopsis balechi. The Bellingshausen Sea was characterized by the lowest salinities and the highest settling volumes (8.7 ml/m3) and cell counts; Laackmanniella spp. and Cymatocylis drygalskii, f. typica dominated this area. Almost all biological variables were significantly intercorrelated, and showed strong and mostly significant negative correlations with surface salinity, yet relationships between enhanced standing stock and ice meltwater were not obvious; rather, highest microplanktonic concentrations seemed to be due to ice-associated growth. Extremely high spatial correlations were found between the tintinnids and the dinoflagellates (r2: 0.941), suggesting the existence of close links between these two groups. Tintinnid species-specific assemblages show a coherent distributional pattern and well defined environment-related trends; most clearly differentiated preferences are exhibited by Laackmanniella prolongata (closely associated with ice-covered areas), Cymatocylis affinis/convallaria (oligotrophic open-ocean waters), and Codonellopsis balechi (coastal regions).  相似文献   

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The distribution of the tick Ixodes uriae is studied in the South Shetlands and different locations along the Antarctic Peninsula. Ticks were found beneath stones close to penguin rookeries of chinstrap, gentoo and adelie penguin, although no individuals were found parasitized. Our results showed that ticks are not distributed evenly along the Antarctic Peninsula being more common and abundant in the northern part with relative abundances of ticks ranging from 1 to 57 individuals per stone and from 2 to 26% of the stone inspected. Ticks are probably absent in the south.  相似文献   

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Cyanobacteria and eukaryotic algae, together with bacteria and fungi, are known to be primary colonizers of mineral soils throughout Antarctica. Their species diversity and soil coverage were studied in 18 soil polygons located at Cierva Point, Antarctic Peninsula. Undisturbed assemblages were dominated by filamentous Cyanobacteria and diatoms, whilst almost 40% of the 49 species recorded were observed only after enrichment culture. Nearly all of the isolates from enrichment cultures were Chlorophyta and Tribophyceae. This revealed a higher degree of complexity than reported for similar communities on Signy Island. Water content and concentrations of nutrients were determined at four representative sites, and did not appear to account for the large inter-polygon variation found in species composition and relative frequencies of occurrence. Variables describing community development were not significantly correlated with either area of the polygons or the minimum distance between them. This suggested that these features are not an important short-range barrier to dispersal for those “weed” species dominating the community. Conversely, the relative frequencies of some of the most common species showed significant correlations with species diversity and soil coverage, and it is suggested that biotic interactions could account to a larger extent for community structure than previously reported from Signy Island fellfields. Accepted: 12 October 1999  相似文献   

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The diversity, ecology and biogeography of diatoms in lakes, seepage areas and streams on the Ulu Peninsula, a large ice-free area in the northern part of James Ross Island (Weddell Sea), were studied. A diverse diatom flora of 123 taxa was observed, dominated by several Nitzschia taxa, Psammothidium papilio, Eolimna jamesrossensis, Fragilaria capucina and Fistulifera saprophila. The results from the similarity and diversity analysis suggest James Ross Island to be biogeographically positioned within the Maritime Antarctic region, yet with some affinities with the flora of Continental Antarctica, as shown by the presence of Luticola gaussii and Achnanthes taylorensis. Based on our data, James Ross Island can thus be located close to the boundary of the two main Antarctic biogeographical regions. Diatom communities present in streams and seepage areas could be clearly distinguished from those in lakes, the latter being much more species rich. Based on the multivariate analysis, conductivity and nutrients were selected as the two main environmental factors determining the diatom composition in the Ulu Peninsula lakes. The revised taxonomy of the Antarctic diatom flora induced the construction of a transfer function for water conductivity in the studied lakes that can be applied in further palaeoecological studies.  相似文献   

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During the austral summers of 2003 and 2006, two cruise were carried out in the Bellingshausen Sea and west off Antarctic Peninsula on board of RV Hespérides. Samples were collected at 26 stations with a multinet Macer-GIROQ sled. A total of 557 cumaceans belonging to 36 species of five families were collected. Nannastacidae was the most abundant and speciose family. Hemilamprops pellucidus and Cyclaspis gigas were the most frequently collected species (38.5% of sampling stations). Cumella asutralis reached the highest density (514.7 individuals/1,000 m2 at stn 7). Maximum species richness (S = 15) and diversity (H′ = 3.53) was observed at one of the deepest station. Positive correlations were found between the cumacean distribution and the organic content and percentage of coarse sand of the sediments. Predominance of Nannastacidae in front of other cumaceans could be explained by their type of feeding (i.e. predators or scavengers), which may be more successful in the deep seafloor of an oligotrophic sea such as studied herein. The presence in the deepest sampling sites of species shared with faunas of surrounding oceans suggests a link between these faunas and those of deep Antarctic waters.  相似文献   

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The phytoplankton [chlorophyll a (Chl a)], microzooplankton,mesozooplankton and macrozooplankton biomass and distributionwere studied as part of a multidisciplinary project (Tempano)along the Antarctic Peninsula during December 2002. Even thoughthe summer phytoplankton bloom was not yet developed in thearea, autotrophs dominated the plankton biomass. Phytoplanktonvertical distribution was, in general, homogeneous in the upper40–50 m of the water column, further decreasing with depth.Protozoans showed low biomass; their contribution to the totalplankton being one order of magnitude lower than that of autotrophs.The vertical distribution of protozoans was variable among stationswith marked peaks at depths ranging from 30 to 80 m. Mesozooplankton-integratedbiomass was generally low, although there was a notable increasesouthward near the ice marginal zone. Macrozooplankton distributionwas more variable without any clear zonal distribution pattern.The vertical distribution of meso- and macrozooplankton (>4mm) biomass showed clear peaks of abundance comprising differentspecies depending on the geographical area. Our biomass distributiondata suggest a food-web scenario in which macrozooplankton arepreying on mesozooplankton populations only in the northernerstations, and mesozooplankton are, in their turn, shaping theabundance of the emerging populations of microzooplankton. Phytoplankton,on the other hand, seem to be hardly controlled by grazing activity.  相似文献   

15.
Life expectancy, especially in the older age groups, is growing enormously due to better social and medical care. According to published data on disabled people (1997), about 30 % of the total population (7,119,000) in Austria suffer from at least one physical disability. In this study, data from a micro census as well as a report from the Federal Ministry for Social Security and Generations is analyzed to illuminate the situation of impaired people with a focus on the capital Vienna. Among other results, it is anticipated that a large number of disabled people receive no help at all. About every 7th person regularly receives care, every 10th receives daily support. Care intensity increases with age showing a clear progression from the age of 60 onwards. 88% of the main supporting individuals are related to the handicapped person being supported. Women generally exhibit a much higher participation in nursing. The socio-political developments are discussed.  相似文献   

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Historically wildlife conservation was based on habitat protection and exploitation control. Only recently have diseases been considered an important issue. However, pathogens are usually described during or after disease outbreaks, but to determine which pathogens may be emerging, surveys of wildlife health are critical in a given time. This study deals with the health status of gentoo penguins Pygoscelis papua in two localities at the Antarctica Peninsula and one at Ardley Island off the South Shetland Islands. Cloacal swaps, fresh fecal samples, ectoparasites, and blood smears were collected. We examined and dissected 14 penguin corpses found dead. Fecal samples were positive for Campylobacter, Escherichia coli and in the carcasses four endoparasitic species were found: Diphyllobothrium sp. and Parorchites zederi, Corynosoma shackletoni and Stegophorus adeliae. The tick Ixodes uriae occurred in five of the examined penguins, and the louse Austrogoniodes gressitti on six birds. From the colony grounds, we collected 1,184 I. uriae. We recorded antibiotic-resistant bacteria, such as E. coli, in ecosystems where gentoo penguins breed. Cloacal samples (300) were negative for Chlamydia, as well as for Salmonella, Campylobacter, E. coli, Newcastle and Influenza viruses.  相似文献   

17.
We present the first regional map of vegetation of anywhere on the Antarctic continent based on remote sensing (RS) data. We have used a normalized difference vegetation index (NDVI) for the examination of Landsat ETM data on the Antarctic Peninsula. The results show that 44.6 km2 (0.086%) of the study area (74,468 km2) is classed with a probability of vegetation of over 50%. The NDVI analysis is ground-truthed against vegetation surveys in Ryder Bay on the Antarctic Peninsula, and the results have been corrected for several factors influencing low NDVI readings in this environment. This methodology has been applied to 13 Landsat scenes covering Graham Land in the Northern part of the Antarctic Peninsula to examine the distribution of vegetation in the region. The Antarctic Peninsula region is important, as it has shown rapid warming of over 3°C during the past 50 years, and predictions indicate accelerated future warming. A baseline survey of the amount and distribution of vegetation is required against which to monitor future change. The results give a comprehensive coverage and allow us to present the first remote sensing-based vegetation map in Antarctica. However, initial results point to the need for further investigation of apparent errors resulting from geology on bare ground.  相似文献   

18.
The ways in which cells communicate among each other concerns all aspects of biology, from developmental processes to diseases. Nitric oxide (NO) is one of the most remarkable and unusual regulatory molecules. It is a labile free radical gas that is not stored but generated on demand, and has been implicated in an extraordinarily diverse range of physiological and pathophysiological functions. The modulation of cell signalling by free radicals is an emerging area of research that provides insight into the orchestration of cell adaptation to a changing microenvironment. In a multicellular organism this serves to coordinate complex physiological responses, such as inflammation. Cell signalling is also accompanied by rapid remodelling of membrane lipids by activated lipases. The discovery that NO, which does not reversibly interact with membrane receptors like conventional hormones and growth factors, targets enzymes such as phospholipase A2, sphingomyelinases or ceramidases, has stimulated growing interest in the crosstalk between redox and lipid signalling.  相似文献   

19.
Summary Immunochemical characterization of proteins from Antarctic krill (E. superba) and particularly serine proteinases was performed by crossed immunoelectrophoresis (CIE). A reference pattern with 34 arbitrarly numbered immunoprecipitates was established for a crude krill extract using IgG rabbit antiserum. A zymographic technique for detection of proteolytic activity was applied and revealed 4 casein-positive antigens. Introduction of different affinity media as intermediate gels in CIE demonstrated several proteins which strongly interacted with Sepharose-bound arginine and Con A. These results suggest the presence of trypsin-like enzymes and other serine proteases and a high content of glycoproteins with alfa-D-mannopyranoside and alfa-D-glycopyranoside residues. The CIE method thus offers a reliable and reproducible tool for identification and characterization of different krill enzymes as well as application in process control, when purifying individual proteins/enzymes. Moreover this technology may serve as a fingerprinting method suitable for biological studies such as classification of geographical subpopulations, genotyping a specific species as well as comparisons between different species.  相似文献   

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Twenty-two species of benthic hydroids, belonging to ten families and 14 genera, were found in a hydroid collection obtained in the Balleny Islands during the BioRoss expedition with the NIWA research vessel Tangaroa in 2004. Twenty of those species constitute new records for the Balleny Islands, raising the total number of known species in the area to 25. Most are members of the subclass Leptothecata, although the subclass Anthoathecata is also relatively well represented. Kirchenpaueriidae and Sertulariidae constitute families with the greatest numbers of species in the collection, with five species (20%) each. Oswaldella with five species (20%) and Staurotheca with four (16%), were the most diverse genera. Twelve species (63%) are endemic to Antarctic waters, most of them with a circum-Antarctic distribution, and 17 (89%) are restricted to Antarctic or Antarctic/sub-Antarctic waters. Although the Balleny Islands hydroid fauna seems to be a typical Antarctic assemblage, it has some striking peculiarities, namely the absence or low representation of some typical and widespread Antarctic genera (Antarctoscyphus and Schizotricha/Symplectoscyphus, respectively).  相似文献   

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