摘要:

About 2000 breeding pairs of Adélie penguin (Pygoscelis adeliaë)nest in Edmonson Point (Wood Bay, 74°21’ S, 165°10’ E). The penguin colony is located on a raised terrace, divided into 13 discrete small units or colonies separated by unoccupied areas, where South polar skua (Catharacta maccormicki) nest. Colony layout, breeding chronology, breeding success, diet, and foraging areas were studied for five consecutive austral summers. Satellite transmitters, time‐depth recorders, and electronic tagging were used for monitoring feeding behaviour and nest attendance. An Automated Penguin Monitoring System was installed which records weight, identity, and direction of penguins as they move between the sea and their breeding colony. So far, the results of this study are documentation on colony trends, breeding biology, and differences in foraging strategies at different stages of the reproductive period and during different study seasons.

ISSN:1125-0003    

DOI:10.1080/11250000009356369

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Results of analyses on pico, nano‐ and microphytoplankton from the sea‐ice of Terra Nova Bay, during austral summer 1995–96, are reported. In this environment, among the 116 taxa that we found, the most abundant were diatoms (102). The interior algal community of the sea‐ice was dominated byFragilariopsisspp.,Archeomonas areolata,and hypnozygotes ofPorella glacialis.In the algal mat at the deeper layer of the ice, however, diatoms showed higher density. Photoautotrophic picoplankton was also present and red‐fluorescing cells, small eukaryotes and phycocyanin‐rich cyanobacteria prevailed over phycoerythrin‐rich cyanobacteria. Besides these data, ultrastructural, physiological and biomolecular surveys on three Antarctic sea water microalgae, of which onlyKoliella antarcticawas known, were also carried out. The 18S rDNA gene sequences ofK. antarcticaand other closely related species allowed us to verify that theKoliellagenus belongs to Trebouxiophyceae, while as regards the other two taxa, one of them was found to belong to theHeterococcusand the other to thePyramimonasgenus. They might be unde‐scribed species of the Southern Ocean.Pyramimonassp., found in Terra Nova Bay during the austral summer 1998–99, carried tri‐chocysts. Moreover,K. antartica,likeHeterococcussp., showed great ability to live both in fresh water and at different salinities.

ISSN:1125-0003    

DOI:10.1080/11250000009356370

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Total concentrations of major and trace elements were determined in thalli of the epilithic lichenUmbilicaria decussatafrom 37 habitats in Victoria Land (continental Antarctica). Average concentrations of Pb, Cu, Zn, Cr, Mn and Fe were among the lowest ever reported for lichens of genusUmbilicaria.On the contrary, Cd and Hg concentrations fell within the same range or were higher than those usually measured in samples from remote areas of the southern and northern hemispheres. No impact of local or remote human activities was detected. Comparison between average metal concentrations inU. decussatasamples collected in 1989 and 1999 did not show significant variations, and this result was assumed to be indicative of negligible changes in the environmental biogeochemistry of Antarctic terrestrial ecosystems. The ad/absorption of soil and rock dust particles, atmospheric depositions, marine aerosols, guano of seabirds, and the uptake of soluble elements from widespread salt encrustations and/or rock minerals are the main sources of major and trace elements for epilithic lichens in continental Antarctica. Although the present results can be taken as baseline levels, further research is necessary in view of the expected effects of climatic changes on element bioavailability in ice‐free areas of Antarctica.

ISSN:1125-0003    

DOI:10.1080/11250000009356371

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Cryptoendolithic microbial communities, living in porous sandstone rocks in the McMurdo Dry Valleys (Ross Desert) of Southern Victoria Land, Antarctica, were found within weathered pegmatite rocks in Northern Victoria Land, and the first endemic Antarctic fungal genusFriedmanniomyces endolithicusanam.‐gen. and sp. nov. was isolated from this community. Selected microfungi from these communities and from soil were examined for the production of extracellular enzymes and antibiotic substances. The cryptoendolithic strain CCFEE 5001 was particularly remarkable for consistent glycosidase activity, coupled with barely detectable growth. Chitinase activity was highest in the soil mi‐crofungusVerticilliumcfr.lecanii(CCFEE 5003). This strain and its purified chitinase were active onMucor plumbeus, Cladospori‐um cladosporioides, Aspergillus versicolor,andPenicillium verrucosum,producing mycelial damage and cell lysis. The strain CCFEE 5020, isolated from rocks, showed antibiotic activity againstPseudomonas putida, Sarcinasp.,Bacillus subtilis,andEscherichia coli,under the test conditions. Good antibiotic activity was produced in the temperature range of 5° to 25° C, pH 4.0, agitation at 700 rpm, and areation at 1.0 vvm, in media containing 0.5% substrate sugar, though this supported only minimal growth. The investigation of soil microfungi in contrasting sites at the BIOTAS area at Edmonson Point indicated that both the presence of bird colonies and changes in temperature and UV exposure obtained by using plastic cloches influenced species composition and density. A ‘Culture Collection of Fungi from Extreme Environments’ (CCFEE) has been established at the University of Tuscia, housing fungal strains from Antarctica.

ISSN:1125-0003    

DOI:10.1080/11250000009356372

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Isolation and classification of extremophiles and cyanobacteria are described. Seven thermophiles, belonging toBacillusgenus, five acidothermophiles, classified asAlicyclobacillus,and five halotolerant cocci, belonging toMicrococcusgenus, were isolated from Antarctic samples of geothermal and saline soils. The isolates were examined for their polar lipid and fatty acid composition. Changes in membrane lipids, induced by stressed growth conditions, were analysed. The isolation of two new cyanobacteria and their polysaccharide characterization were described. The exopolysaccharide production and characterization, as well as thermophilic xylan‐degrading enzymes, were studied.

ISSN:1125-0003    

DOI:10.1080/11250000009356373

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

After a brief summary of previous Italian lichenological research in Antartica, a key is provided for the identification of the 57 species of lichens and lichenicolous fungi which were hitherto recorded from the Terra Nova Bay area (Victoria Land, Continental Antarctica). The key is based on the analysis of the samples collected during the Italian Antarctic expeditions, and preserved in the TSB lichen herbarium. Due to the high incidence of broad‐ranging, often bipolar or subcosmopolitan species, the lichen flora of the survey area seems to be a young one, which mainly originated by long‐distance dispersal in the Quaternary period.

ISSN:1125-0003    

DOI:10.1080/11250000009356374

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:1125-0003    

DOI:10.1080/11250000009356347

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor