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Abstract

Antarctica is perceived as one of the most pristine environments on Earth, though increasing human activities and global climate change raise concerns about preserving the continent’s environmental quality. Limited in distribution, soils are particularly vulnerable to disturbances and pollution, yet lack of baseline studies limits our abilities to recognize and monitor adverse effects of environmental change. To improve the understanding of natural geochemical variability of soils, a survey was conducted in the fellfield environments of Edmonson Point (Victoria Land). Soil samples were analyzed for six major (Fe, Ca, Mg, Na, K and Ti) and 24 trace elements (As, Ba, Be, Bi, Cd, Co, Cr, Cs, Cu, Ga, Li, Mn, Mo, Ni, Pb, Rb, Sn, Sr, Tl, U, V, Y, Zn and Zr). Relationships among element concentrations in the samples and local bedrock were analyzed to identify their origin and similarities in geochemical cycles. Element concentrations in the soils were highly variable but generally within the lowest values reported elsewhere in Antarctica. Though values of Cd, Mn, Ni and Zn were relatively high, they are consistent with those in the local soil-forming rocks indicating an origin from natural sources rather than anthropogenic contamination. Chemical composition of soils vs. rocks pointed to alkali basalts as the lithogenic source of the soil matrix, but also indicated considerable alteration of elemental composition in the soil. Considering local environmental settings, the soil elemental content was likely affected by marine-derived inputs and very active hydrological processes which enhanced leaching and removal of mobilized elements. Both of these processes may be of particular importance within the context of global climate change as the predicted increases in temperature, water availability and length of the summer season would favor mineral weathering and increase geochemical mobility of elements.
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Abstract

Lichens of relict penguin colonies and sites affected by active penguin colonies were investigated in Victoria Land, Ross Sea sector, continental Antarctica. A total of 17 coastal sites, seven in northern and ten in southern Victoria Land, have been investigated across 7 ° of latitude from 71 ° to 78 ° S. Altogether 40 taxa of lichens have been identified. Four of the recorded species are new to the Antarctic – Caloplaca erecta , C. soropelta , C. tominii and Physcia tenella ; two species are new to the Victoria Land area – Lecania nylanderiana and Lecanora polytropa . The first lichen records from Beaufort Island are also provided. Data presented here expand the knowledge on the occurrence, diversity and distribution of Victoria Land lichens.
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Abstract

We assessed culturable soil microfungal diversity in various habitats around Hornsund, Spitsbergen in the High Arctic, using potato dextrose agar ( PDA) medium. Thermal growth classification of the fungi obtained was determined by incubating them in 4 ° Cand 25 ° C, permitting separation of those with psychrophilic, psychrotolerant and mesophilic characteristics. In total, 68 fungal isolates were obtained from 12 soil samples, and grouped into 38 mycelial morphotypes. Intergenic spacer regions of these morphotypes were sequenced, and they represented 25 distinct taxonomic units, of which 21 showed sufficient similarity with available sequence data in NCBI to be identified to species level. Soil under ornithogenic influence showed the highest species diversity, including sequences assigned to Mortierella macrocystis, M. elongata, Mortierella sp., Cudoniella sp., Varicosporium elodeae , Beauveria bassiana , Geomyces pannorum , Penicillium sp. and Atradidymella muscivora . Fourteen taxa were classified as psychrophilic, seven mesophilic, and four psychrotolerant.
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Abstract

A filamentous benthic cyanobacteria, strain USMAC16, was isolated from the High Arctic Svalbard archipelago, Norway, and a combination of morphological, ultrastructural and molecular characterisation (16S rRNA gene sequence) used to identify to species level. Cell dimensions, thylakoid arrangement and apical cell shape are consistent with the Pseudanabaena genus description. The molecular characterisation of P. catenata gave 100% similarity with Pseudanabaena catenata SAG 1464-1, originally reported from Germany. Strain USMAC16 was cultured under a range of temperature and photoperiod conditions, in solid and liquid media, and harvested at exponential phase to examine its phenotypic plasticity. Under different culture conditions, we observed considerable variations in cell dimensions. The longest cell (5.91±0.13 μm) was observed at 15°C under 12:12 light:dark, and the widest cell (3.24±0.06 μm) at 4°C under 12:12 light: dark in liquid media. The study provides baseline data documenting the morphological variation of P. catenata in response to changing temperature regimes.
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