Field photosynthetic activity of lichens in the Windmill Islands oasis, Wilkes Land, continental Antarctica

In order to ascertain whether the major species of continental antarctic macrolichens are photosynthetically active during summer conditions, the chlorophyll fluorescence of three lichen species [Umbilicarin decussata (Vill. Zahlbr., Pseudephebe minuscula (Ny-l. ex Arnold) Brodo and Hawksw. and Usnea sphacetala R. Br.] was monitored in the vicinity of Casey Station. Wilkes Land, continental Antarctica using a PAM-2000 modulated fluorescence system. Lichens were studied when in equilibrium with the atmosphere as well as when moistened by snow showers. Photochemical quantum yield was estimated as ΔF/F′_m and related to thallus water content as well as microclimatic conditions. Lichens were photosynthetically active only when moistened by snow fall or by run-off from snow melt. The levels of photosynthetic activity in the field for all species were influenced by microenvironmental conditions and patterns in response were site and species specific. Highest levels of photosynthetic efficiency occurred when thalli were at intermediate water contents. Photosynthetic activity was reduced by cold as well as warm, bright conditions. Highest thallus water contents occurred during the middle of the day after substantial “falls of snow. P. minuscula maintained highest thallus water contents at all sites and appears to have a high water compensation point which is related to its observed distribution patterns. Umbilicaria decussata studied in the laboratory did not become photosynthetically active even when exposed to 95% relative humidity (RH) for 51 h and. when dehydrating after artificial wetting, showed an optimum thallus water content for photosynthesis of ca 90% dry weight and a thallus water compensation point of about 35% dry weighl. In the field U. decussata did not become pholosynthetically active except when moistened by snow. Usnea sphacelata exposed to the atmosphere had low thallus water contents (ca 30%) which was not related to RH. The results indicate that the lichens are photosynthetically inactive for most of the summer period and are totally reliant on snow as a water supply. This i.s important when modelling carbon gain and growth rates of continental antarctic lichens.     

Phytogeography of bryophyte and lichen vegetation in the Windmill Islands,Wilkes Land,Continental Antarctica

The distribution and frequency of bryophyte and lichen vegetation on ice-free regions of the Windmill Islands are presented using data derived from aerial photography and ground surveying. The qualitative and quantitative plant cover of sites are listed and related to the topography and major soil characteristics of each site. The richest associations of macrolichens and bryophytes occurred on the metamorphic northern peninsulas. Species richness and frequency was generally reduced on the charnockitic southern peninsula and the islands which have been deglaciated longer. Salinity varied significantly throughout the region with the highest levels in the northern islands reflecting the presence of penguin colonies. In such sites bryophytes and lichens were virtually absent. Wind blown sea-spray contributed far less salts than direct excretion from penguins. On the peninsulas snow cover and site exposure appeared to delimit plant distribution. Higher salt levels from sea-spray on the northern aspects of the peninsulas seemed to have negligible impact on vegetation patterns with the possible exception ofBiatorella cerebriformis which was encountered only inland. The total phosphorus and nitrogen levels of the skeletal soils were generally low except in eutrophic sites adjacent to penguin colonies. The vegetation patterns are discussed in terms of the climate, topography and species autecology.     

Moss Communities and Their Characteristics in Ice-free Areas of the Windmill Islands,Wilkes Land,Continental Antarctica

The moss vegetation of the Windmill Islands can be classified into the following seven communities: 1.Grimmia antarctici community; 2. G. antarctici-Ceratodon purpureus community; 3. Bryum pseudotriquetrum community; 4. G. antarctici-B, pseudotriquetrum community; 5. Ceratodon purpureus community; 6. C. purpureus-G, antarctici community; 7. C. purpureus B. pseudotriquetrum community. Communities 1, 3, 4 and 7 occur in wet habitats while communities 5 and 6 are found in rather dry habitats, community 2 distributes between dry and wet habitats. Microtopography governs the distribution of water supply and therefore community types. Stable moss communities usually form moss hummocks and hollows. Species composition, colour and height of the hummocks determines the vertical structure of the moss community layers with 2-3 strata being discernible and level structure forming mosaic. Other phytocoenological characteristics of the moss communities, such as the dense moss cushions, asexual reproduction (although antheridia or archegonia have been found in each of the species), abundance of epiphytic algae and lichens growing on the surface of moss hummocks, the colour change of some species in different habitats, appear related to moisture availability, light intensity, wind exposure and temperature.     

The broad-scale distribution of microfungi in the Windmill Islands region, continental Antarctica

Microfungi were isolated from soils, mosses, algae and lichens in the Windmill Islands region of Antarctica. From a total of 1,228 isolates, 22 genera were identified. The most frequently isolated fungi from mosses were Mycelia sterilia (47% of total isolates), Phoma spp. (18%), Penicillium spp. (11%), Chrysosporium spp. (7%) and Thelebolus microsporus (6%). Mycelia sterilia, Penicillium spp., Mortierella spp., Chrysosporium cf. pannorum and Thelebolus microsporus were also frequently isolated from algae. Fungal distribution and diversity were poor in samples of lichens, compared to samples from mosses and algae. The frequency of occurrence of microfungi was most often associated with strong biotic influence. There was a marked increase in fungal diversity in human-disturbed sites. Twelve taxa were restricted to soils from near the Australian Casey Station, suggesting significant introduction of fungi into this environment by human activities. Away from the station, fungal distribution appeared to be related to substrata and nutrient status rather than dispersal opportunities. Suggestions for future research and the need for constant monitoring to clarify the role of human disturbance on Antarctic fungi are discussed. Received: 1 April 1997 / Accepted: 17 August 1997     

Snow algae of the Windmill Islands, continental Antarctica 3. Chloromonas polyptera (Volvocales, Chlorophyta)

A new name, Chloromonas hohamii, is proposed to accommodate a common North American snow alga previously incorrectly referred to as Chloromonas polyptera. Chloromonas hohamii differs in having the motile vegetative cells with a cup-shaped chloroplast opening in the anterior end of the cell, shorter, narrower, ellipsoidal to elongate to somewhat fusiform, sexual spores with non-spiralled wall flanges, shorter and narrower daughter cells derived from the spores, and it grows in snow of significantly lower pH and conductivity. Received: 29 August 1997 / Accepted: 24 April 1998     

10. Snow algae of the Windmill Islands region, Antarctica

A list of the 24 species of snow algae identified from the region, a resume of what is currently known about the major species, and avenues for further research are provided. New species discovered include 2 Desmotetra spp., one Chlorosarcina sp., 2 Chloromonas spp. and a Palmellopsis sp. Several of these are from genera whose members have previously been found only in the soil flora. Not only was it necessary to elucidate the life cycle of these species, but it was also essential to examine them ultrastructurally to determine their taxonomic positions.     

Monitoring of a Southern Giant Petrel Macronectes giganteus population on the Frazier Islands, Wilkes Land, Antarctica

Since 1956, Southern Giant Petrels on the Frazier Islands, East Antarctica, have been counted with different census techniques, sometimes varying within seasons and among islands, which hindered analysis of the data. Protective measures for the islands from 1986 onwards have increased the need for reliable long-term census data, but reduced the ways to collect these data. Published and unpublished data were re-examined, and population trends were reconstructed based on two relatively standardised techniques: the number of active chicks (AC) and the number of apparently occupied nests (AON) around hatching. AC-values from Nelly Island from 1959 to 1998 indicate substantial periodic fluctuations, but no consistent long-term change. Since the late 1970s, AC-values on the other two islands and AON-values suggest that the breeding population may have grown by 35%. This recent growth, however, is within the extent of periodic fluctuations observed in Southern Giant Petrel population that is stable over the long term.     

Filamentous fungi of the Windmill Islands, continental Antarctica. Effect of water content in moss turves on fungal diversity

This study presents the effect of water content in moss turves from the Windmill Islands, Wilkes Land, continental Antarctica on the composition of associated filamentous fungi. The two most prevalent mosses were sampled: Grimmia antarctici and Bryum pseudotriquetrum. Results were expressed as dry weights. No relationship was found between water content of the mosses or the surrounding soil and fungal diversity. Ten species of fungi were recovered and all species belong to cosmopolitan taxa. Accepted: 21 June 1999     

Isolates of Arthrobacter from the soils of Schirmacher Oasis,Antarctica

Summary Thirteen isolates of bacteria from the soils of Schirmacher Oasis, Antarctica have been identified as members of the genus Arthrobacter. All the isolates exhibited a rod-coccus cycle during growth; were gram positive, catalase positive, non-motile and non-fermentative; did not form endospores; and contained MK-8 (H₂) as the major menaquinone. The mole %G + C in DNA of the isolates ranged from 58% to 72%. Based on their morphology, physiology, nutritional requirements, biochemical characteristics, and mole %G + C of their DNA, the isolates were identified as A. globiformis, A. pascens and A. protophormiae. However, unlike the mesophilic isolates the Antarctic Arthrobacter could be considered to be unique as they were psychrotrophic, contained glucose and lysine in the cell wall, and did not hydrolyze starch.     

Tardigrades of the Australian Antarctic Territories: the Windmill Islands, East Antarctica

Six species of tardigrades, Pseudechiniscus suillus, Macrobiotus sp., Hypsibius antarcticus, Ramajendas frigidus, Diphascon chilenense and Diphascon pingue were extracted from mosses and lichens from the ice-free regions of the Windmill Islands near Casey Base, East Antarctica. Significant positive associations were found between the three common species ( Pseudechiniscus suillus, Hypsibius antarcticus, Diphascon chilenense ) and bryophytes, whereas strong negative associations were found between these species and algae and lichens. There were additional interspecific associations between the common species of tardigrades as well as between tardigrades, nematodes and rotifers.     

Fungi of the Windmill Islands, continental Antarctica. Effect of temperature, pH and culture media on the growth of selected microfungi

Studies were conducted on microfungi isolated from soils in the Windmill Islands, continental Antarctica. Growth responses of Alternaria alternata, Chrysosporium pannorum, Nectria peziza, Thelebolus microsporus, Mycelia sterile and Phoma cf. herbarum to temperature, pH and culture media were investigated. Maximum growth occurred after 16 days, except in Nectria peziza and Thelebolus microsporus, where maximum growth occurred 12 days after inoculation. All isolates showed poor growth at 0°C. Maximum growth was obtained with temperatures ranging from 15 to 25°C. The optimum temperature for all fungi was 20°C. An acid medium favoured growth. Chrysosporium pannorum, Phoma cf. herbarum and Nectria peziza grew best at pH 3–4, whereas Mycelia sterile, Alternaria alternata and Thelebolus microsporus grew best at pH 5–6. The culture medium had little effect on growth, except for nutrient agar, which showed poor growth against all isolates with the exception of Thelebolus microsporus. Received: 11 September 1996 / Accepted: 13 January 1997     

Abundance and diversity of soil invertebrates in the Windmill Islands region,East Antarctica

The harsh climate and patchy distribution of habitable terrestrial ecosystems constrain soil invertebrate communities in continental Antarctica. The Windmill Islands in East Antarctica have a relatively gentle climate by Antarctic standards, and the region supports some of the most well-developed moss beds on the continent. These moss beds and soils are known to sustain invertebrate communities dominated by nematodes, rotifers and tardigrades, but our knowledge of the diversity and composition of these communities remains limited. We extracted soil fauna from 74 soil samples representing a wide range of microhabitats, and 24 moss samples, collected at Clark Peninsula, Bailey Peninsula and Robinson Ridge in the Windmill Islands during the 2012–2013 austral summer. Invertebrates were present in all samples, but densities varied considerably both within and between sites with limited correlation with edaphic variables or cover type. Taxa found included two species of nematodes (Plectus murrayi; Plectus frigophilus), one mite (Nanorchestes antarcticus) as well as tardigrades and rotifers (enumerated only). No springtails were found in this study, but individuals of the genus Cryptopygus were later recovered from moss collected near Casey Station. The Windmill Islands soils and moss beds support dense populations of soil fauna. However, despite the relatively mild climate conditions and favorable soil properties, species diversity is low. The diversity is possibly limited by recent deglaciation and limited dispersal opportunities to the region. Given favorable local conditions, it is likely that colonizing species will perform well, whether these arrive by natural means or are accidentally introduced by humans.     

Biosurfactant Production by Halotolerant Rhodococcus fascians from Casey Station, Wilkes Land, Antarctica

Isolate A-3 from Antarctic soil in Casey Station, Wilkes Land, was characterized for growth on hydrocarbons. Use of glucose or kerosene as a sole carbon source in the culture medium favoured biosynthesis of surfactant which, by thin-layer chromatography, indicated the formation of a rhamnose-containing glycolipid. This compound lowered the surface tension at the air/water interface to 27 mN/m as well as inhibited the growth of B. subtilis ATCC 6633 and exhibited hemolytic activity. A highly hydrophobic surface of the cells suggests that uptake occurs via a direct cell–hydrocarbon substrate contact. Strain A-3 is Gram-positive, halotolerant, catalase positive, urease negative and has rod–coccus shape. Its cell walls contained meso-diaminopimelic acid. Phylogenetic analysis based on comparative analysis of 16S rRNA gene sequences revealed that strain A-3 is closely related to Rhodococcus fascians with which it shares 100% sequence similarity. This is the first report on rhamnose-containing biosurfactant production by Rhodococcus fascians isolated from Antarctic soil.     

Classification and ordination of cryptogamic communities in Wilkes Land,Continental Antarctica

The entirely cryptogamic vegetation of Bailey and Clark Peninsulas, Windmill Islands, Budd Coast, Wilkes Land, Antarctica, is described for the first time. The vegetation of this area is exceptionally well developed and diverse and represents one of the most important botanical sites on the continent. The macroflora comprises three species of moss, one liverwort, three fruticose lichens, four foliose and over 20 crustose lichens; several macroalgae also occur. Seventy stands of relatively homogeneous vegetation were analysed and the percentage cover afforded by every species within 20 quadrats per site was recorded. A subjective classification was developed by visual ordering of the data sets and a hierarchical system erected which incorporates one moss- and one lichen-dominated sub-formation; the former includes two associations and seven sociations, while the latter comprises one association which includes four sociations. The data were then arranged by centroid linkage analysis to produce and objective classification, and subsequently ordinated by principal components analysis to generate groups of stands, the inter-relations of which were interpreted in ecological and environmental terms. The objective classification and ordination strongly support the subjectively derived groupings or sociations. Examples of plant interactions are qualitatively described.     

Penicillium species from terrestrial habitats in the Windmill Islands, East Antarctica, including a new species, Penicillium antarcticum

This paper documents the Penicillium species associated with the naturally occurring plants and animals in the Windmill Islands, East Antarctica. An attempt has been made to establish the species associations between the Penicillia and the mosses and birds. The species found are discussed briefly in terms of taxonomy and biological significance, and a new species, Penicillium antarcticum, is described. Accepted: 27 July 1998     

Foods of the South Polar skua Catharacta maccormicki at Ardery Island, Windmill Islands, Antarctica

South Polar skuas (Catharacta maccormicki) breed on Ardery Island in the absence of a local breeding population of Adelie penguins (Pygoscelis adeliae). Assessment was made of the food remains in skua feeding territories in 1995/1996. The diet of South Polar skuas largely consisted of fulmarine petrel species which bred on Ardery Island. Southern fulmar (Fulmarus glacialoides) remains were the predominant prey items found, and skuas appeared to feed preferentially on this species. Accepted: 3 June 2000     

Biological monitoring of heavy-metal contamination in coastal waters off Casey Station, Windmill Islands, East Antarctica

Heavy-metal concentrations were determined in tissues of different species of benthic invertebrates collected in the Casey region (Australian Antarctic Territory) where an old waste-disposal tip site is a source of contamination. The species studied included the bivalve Laternula elliptica, starfish Notasterias armata, heart urchins Abatus nimrodi and A. ingens and gammaridean amphipod Paramoera walkeri. The specimens were collected at both reference and contaminated locations where lead was the priority element and copper was the next most important in terms of increased concentrations. The strong association between a gradient of contamination and concentrations in all species tested indicates that they are reflecting well the environmental changes, and that they appear as appropriate biological indicators of heavy-metal contamination. Aspects of the biology of species with different functional roles in the marine ecosystem are discussed in relation to their suitability for wider use in Antarctic monitoring programmes. For example, in terms of heavy-metal bioaccumulation, the bivalve appears as the most sensitive species to detect contamination; the starfish provides information on the transfer of metals through the food web while the heart urchin and gammarid give indications of the spatial and temporal patterns of the environmental contamination. The information gathered about processes of contaminant uptake and partitioning among different tissues and species could be used in later studies to investigate the behaviour and the source of contaminants.     

Production of antibiotics and enzymes by soil microorganisms from the windmill islands region, Wilkes Land, East Antarctica

The distribution of microorganisms in four soil samples taken near Casey Station, Wilkes Land, and on Dewart Island, Frazier Islands (East Antarctica), was studied using isolation cultures at different temperatures. The fungal assemblages comprised Penicillium, Alternaria, Cladosporium, Phoma, Verticillium, Phialophora, Candida and Rhodotorula. Microalgal Chlorophyta were also common. Among the bacteria representatives of cyanobacteria, Staphylococcus, Bacillus, Pantoea, Streptomyces, Micromonospora, and coryne- and nocardioform species were found. Some of the isolated actinomycete strains, determined as Arthrobacter, Rhodococcus, Streptomyces and Micromonospora, produced extracellular substances with antibacterial and antifungal activities. Their potential as biological agents against phytopathogenic bacteria and fungi is discussed.     

Ecology of the active soil microfauna (Protozoa, Metazoa) of Wilkes Land, East Antarctica

Active ciliates, testate amoebae, nematodes, rotifers and tardigrades were examined in fresh and preserved fellfield, moss and ornithogenic soil samples of Wilkes Land. Direct counting was used to investigate abundances, community structures and protozoan diversity. Twenty-six ciliate species (nine first records for continental Antarctica, one undescribed) and five testacean species (three new records) were found. Two Colpoda species were active, further disproving Smith's hypothesis that this genus is absent in continental Antarctica. Animal frequencies varied between habitats but every group occurred in at least 74% of the samples, rotifers (95%) and testaceans (92%) being most frequent. Highest abundances were recorded in moss: 354 ciliates/g dry soil (19 species), 671 testaceans (5 species), 513 nematodes, 1,311 rotifers and 4,607 tardigrades, which thus dominated. Rotifers were most abundant in the other habitats. The microfauna was not randomly distributed because individual numbers were often strongly intercorrelated. Water and organic matter content were relevant environmental parameters; air temperature and pH probably had indirect effects. Received:28 August 1996 / Accepted:23 November 1996