The Antarctic terrestrial environment harbors a diverse community of microorganisms, which have adapted to the extreme conditions. The aim of this study was to describe the composition of microbial communities in a diverse range of terrestrial environments (various biocrusts and soils, sands from ephemeral wetlands, biofilms, endolithic and hypolithic communities) in East Antarctica using both molecular and morphological approaches. Amplicon sequencing of the 16S rRNA gene revealed the dominance of Chloroflexi, Cyanobacteria and Firmicutes, while sequencing of the 18S rRNA gene showed the prevalence of Alveolata, Chloroplastida, Metazoa, and Rhizaria. This study also provided a comprehensive assessment of the microphototrophic community revealing a diversity of cyanobacteria and eukaryotic microalgae in various Antarctic terrestrial samples. Filamentous cyanobacteria belonging to the orders Oscillatoriales and Pseudanabaenales dominated prokaryotic community, while members of Trebouxiophyceae were the most abundant representatives of eukaryotes. In addition, the co-occurrence analysis showed a prevalence of positive correlations with bacterial taxa frequently co-occurring together.

• Keywords
• East Antarctica, amplicon sequencing, cyanobacteria, eukaryotic microalgae, terrestrial environment,
• Publication type
• Journal Article MeSH

A wide range of microorganisms inhabit biocrusts of arctic and sub-arctic regions. These taxa live and thrive under extreme conditions and, moreover, play important roles in biogeochemical cycling. Nevertheless, their diversity and abundance remain ambiguous. Here, we studied microbial community composition in biocrusts from Svalbard and Iceland using amplicon sequencing and epifluorescence microscopy. Sequencing of 16S rRNA gene revealed the dominance of Chloroflexi in the biocrusts from Iceland and Longyearbyen, and Acidobacteria in the biocrusts from Ny-Ålesund and South Svalbard. Within the 18S rRNA gene sequencing dataset, Chloroplastida prevailed in all the samples with dominance of Trebouxiophyceae in the biocrusts from Ny-Ålesund and Embryophyta in the biocrusts from the other localities. Furthermore, cyanobacterial number of cells and biovolume exceeded the microalgal in the biocrusts. Community compositions in the studied sites were correlated to the measured chemical parameters such as conductivity, pH, soil organic matter and mineral nitrogen contents. In addition, co-occurrence analysis showed the dominance of positive potential interactions and, bacterial and eukaryotic taxa co-occurred more frequently together.

• Keywords
• amplicon sequencing, bacteria, biocrusts, co-occurrence, eukaryotes, microbial phototrophs,
• Publication type
• Journal Article MeSH

Cyanobacteria are important colonizers of recently deglaciated proglacial soil but an in-depth investigation of cyanobacterial succession following glacier retreat has not yet been carried out. Here, we report on the successional trajectories of cyanobacterial communities in biological soil crusts (BSCs) along a 100-year deglaciation gradient in three glacier forefields in central Svalbard, High Arctic. Distance from the glacier terminus was used as a proxy for soil age (years since deglaciation), and cyanobacterial abundance and community composition were evaluated by epifluorescence microscopy and pyrosequencing of partial 16S rRNA gene sequences, respectively. Succession was characterized by a decrease in phylotype richness and a marked shift in community structure, resulting in a clear separation between early (10-20 years since deglaciation), mid (30-50 years), and late (80-100 years) communities. Changes in cyanobacterial community structure were mainly connected with soil age and associated shifts in soil chemical composition (mainly moisture, SOC, SMN, K, and Na concentrations). Phylotypes associated with early communities were related either to potentially novel lineages (< 97.5% similar to sequences currently available in GenBank) or lineages predominantly restricted to polar and alpine biotopes, suggesting that the initial colonization of proglacial soil is accomplished by cyanobacteria transported from nearby glacial environments. Late communities, on the other hand, included more widely distributed genotypes, which appear to establish only after the microenvironment has been modified by the pioneering taxa.

• Keywords
• Cyanobacteria, Glacier forefield, High Arctic, High-throughput sequencing, Primary succession, Proglacial soil,
• MeSH
• Biodiversity MeSH
• DNA, Bacterial MeSH
• Phylogeny * MeSH
• Genotype MeSH
• Ice Cover microbiology   MeSH
• Soil chemistry   MeSH
• Soil Microbiology * MeSH
• RNA, Ribosomal, 16S genetics   MeSH
• Cyanobacteria classification   genetics   MeSH
• High-Throughput Nucleotide Sequencing MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Arctic Regions MeSH
• Svalbard MeSH
• Names of Substances
• DNA, Bacterial MeSH
• Soil MeSH
• RNA, Ribosomal, 16S MeSH

The environment of high-altitudinal cold deserts of Western Himalaya is characterized by extensive development of biological soil crusts, with cyanobacteria as dominant component. The knowledge of their taxonomic composition and dependency on soil chemistry and elevation is still fragmentary. We studied the abundance and the phylogenetic diversity of the culturable cyanobacteria and eukaryotic microalgae in soil crusts along altitudinal gradients (4600-5900 m) at two sites in the dry mountains of Ladakh (SW Tibetan Plateau and Eastern Karakoram), using both microscopic and molecular approaches. The effects of environmental factors (altitude, mountain range, and soil physico-chemical parameters) on the composition and biovolume of phototrophs were tested by multivariate redundancy analysis and variance partitioning. Both phylogenetic diversity and composition of morphotypes were similar between Karakorum and Tibetan Plateau. Phylogenetic analysis of 16S rRNA gene revealed strains belonging to at least five genera. Besides clusters of common soil genera, e.g., Microcoleus, Nodosilinea, or Nostoc, two distinct clades of simple trichal taxa were newly discovered. The most abundant cyanobacterial orders were Oscillatoriales and Nostacales, whose biovolume increased with increasing elevation, while that of Chroococales decreased. Cyanobacterial species richness was low in that only 15 morphotypes were detected. The environmental factors accounted for 52 % of the total variability in microbial data, 38.7 % of which was explained solely by soil chemical properties, 14.5 % by altitude, and 8.4 % by mountain range. The elevation, soil phosphate, and magnesium were the most important predictors of soil phototrophic communities in both mountain ranges despite their different bedrocks and origin. The present investigation represents a first record on phylogenetic diversity of the cyanobacterial community of biological soil crusts from Western Himalayas and first record from altitudes over 5000 m.

• Keywords
• Cyanobacterial diversity, Desert, High-elevation, Phosphorus, Soil crusts, Western Himalayas,
• MeSH
• Biodegradation, Environmental MeSH
• Biodiversity * MeSH
• Phylogeny * MeSH
• Geologic Sediments analysis   microbiology   MeSH
• Molecular Sequence Data MeSH
• Altitude MeSH
• Soil chemistry   MeSH
• Soil Microbiology * MeSH
• Cyanobacteria classification   genetics   isolation & purification   metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Tibet MeSH
• Names of Substances
• Soil MeSH

Cyanobacterial diversity in soil crusts has been extensively studied in arid lands of temperate regions, particularly semi-arid steppes and warm deserts. Nevertheless, Arctic soil crusts have received far less attention than their temperate counterparts. Here, we describe the cyanobacterial communities from various types of soil crusts from Svalbard, High Arctic. Four soil crusts at different development stages (ranging from poorly-developed to well-developed soil crusts) were analysed using 454 pyrosequencing of the V3-V4 variable region of the cyanobacterial 16S rRNA gene. Analyses of 95 660 cyanobacterial sequences revealed a dominance of OTUs belonging to the orders Synechococcales, Oscillatoriales and Nostocales. The most dominant OTUs in the four studied sites were related to the filamentous cyanobacteria Leptolyngbya sp. Phylotype richness estimates increased from poorly- to mid-developed soil crusts and decreased in the well-developed lichenized soil crust. Moreover, pH, ammonium and organic carbon concentrations appeared significantly correlated with the cyanobacterial community structure.

• Keywords
• 16S rRNA gene, 454 pyrosequencing, Arctic, cyanobacteria, soil chemistry, soil crust,
• MeSH
• DNA, Bacterial analysis   MeSH
• Lichens genetics   MeSH
• Microbial Consortia * MeSH
• Soil chemistry   MeSH
• Soil Microbiology * MeSH
• RNA, Ribosomal, 16S genetics   MeSH
• Base Sequence MeSH
• Sequence Analysis, DNA MeSH
• Cyanobacteria classification   genetics   MeSH
• Cold Climate MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Arctic Regions MeSH
• Svalbard MeSH
• Names of Substances
• DNA, Bacterial MeSH
• Soil MeSH
• RNA, Ribosomal, 16S MeSH

Successful adaptation/acclimatization to low temperatures in micro-algae is usually connected with production of specific biotechnologically important compounds. In this study, we evaluated the growth characteristics in a micro-scale mass cultivation of the Antarctic soil green alga Chlorella mirabilis under different nitrogen and carbon sources followed by analyses of fatty acid contents. The micro-scale mass cultivation was performed in stable (in-door) and variable (out-door) conditions during winter and/or early spring in the Czech Republic. In the in-door cultivation, the treatments for nitrogen and carbon sources determination included pure Z medium (control, Z), Z medium + 5% glycerol (ZG), Z medium + 5% glycerol + 50 μM KNO3 (ZGN), Z medium + 5% glycerol + 200 μM NH4Cl (ZGA), Z medium + 5% glycerol + 1 mM Na2CO3 (ZNC), Z medium + 5% glycerol + 1 mM Na2CO3 + 200 μM NH4Cl (ZGCA) and Z medium + 5% glycerol + 1 mM Na2CO3 + 50 μM KNO3 (ZGCN) and were performed at 15°C with an irradiance of 75 μmol m(-2) s(-1). During the out-door experiments, the night-day temperature ranged from -6.6 to 17.5°C (daily average 3.1 ± 5.3°C) and irradiance ranged from 0 to 2,300 μmol m(-2) s(-1) (daily average 1,500 ± 1,090 μmol m(-2) s(-1)). Only the Z, ZG, ZGN, and ZGC treatments were used in the out-door cultivation. In the in-door mass cultivation, all nitrogen and carbon sources additions increased the growth rate with the exception of ZGA. When individual sources were considered, only the effect of 5% glycerol addition was significant. On the other hand, the growth rate decreased in the ZG and ZGN treatments in the out-door experiment, probably due to carbon limitation. Fatty acid composition showed increased production of linoleic acid in the glycerol treatments. The studied strain of C. mirabilis is proposed to be a promising source of linoleic acid in low-temperature-mass cultivation biotechnology. This strain is a perspective model organism for biotechnology in low-temperature conditions.

• Keywords
• N and C manipulation, fatty acid content, growth rate, low temperature, microalgae,
• Publication type
• Journal Article MeSH

Although phototrophic microbial communities are important components of soils in arid and semi-arid ecosystems around the world, the knowledge of their taxonomic composition and dependency on soil chemistry and vegetation is still fragmentary. We studied the abundance and the diversity of cyanobacteria and eukaryotic microalgae along altitudinal gradients (3,700-5,970 m) at four sites in the dry mountains of Ladakh (Little Tibet, Zanskar Mountains, and Eastern Karakoram), using epifluorescence. The effects of environmental factors (altitude, mountain range, and vegetation type) on soil physico-chemical parameters (pH; texture; organic matter, nitrogen, ammonia, and phosphorus contents; and concentration of chlorophylls and carotenoids) and on the composition and biovolume of phototrophs were tested by multivariate redundancy analysis and variance partitioning. Phototrophs were identified in all collected samples, and phototroph biovolume ranged from 0.08 to 0.32 mm(3) g(-1) dry weight. The dominant component was cyanobacteria, which represented 70.9% to 98.6% of the biovolume. Cyanobacterial species richness was low in that only 28 morphotypes were detected. The biovolume of Oscillatoriales consisted mainly of Phormidium spp. and Microcoleus vaginatus. The environmental factors accounted for 43.8% of the total variability in microbial and soil data, 20.6% of which was explained solely by mountain range, 7.0% by altitude, and 8.4% by vegetation type. Oscillatoriales prevailed in alpine meadows (which had relatively high organic matter and fine soil texture), while Nostocales dominated in the subnival zone and screes. Eukaryotic microalgae together with cyanobacteria in the order Chroococcales were mostly present in the subnival zone. We conclude that the high elevation, semiarid, and arid soils in Ladakh are suitable habitats for microbial phototrophic communities and that the differences in these communities are associated with site, altitude, and vegetation type.

• MeSH
• Chlorophyll analysis   MeSH
• Microscopy, Fluorescence methods   MeSH
• Phototrophic Processes MeSH
• Microalgae growth & development   MeSH
• Multivariate Analysis MeSH
• Altitude * MeSH
• Soil chemistry   MeSH
• Soil Microbiology * MeSH
• Cyanobacteria growth & development   MeSH
• Biota MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Tibet MeSH
• Names of Substances
• Chlorophyll MeSH
• Soil MeSH

Microbial communities occurring in three types of supraglacial habitats--cryoconite holes, medial moraines, and supraglacial kames--at several glaciers in the Arctic archipelago of Svalbard were investigated. Abundance, biovolume, and community structure were evaluated by using epifluorescence microscopy and culturing methods. Particular emphasis was laid on distinctions in the chemical and physical properties of the supraglacial habitats and their relation to the microbial communities, and quantitative multivariate analyses were used to assess potential relationships. Varying pH (4.8 in cryoconite; 8.5 in a moraine) and texture (the proportion of coarse fraction 2% of dry weight in cryoconite; 99% dw in a kame) were found, and rather low concentrations of organic matter (0.3% of dry weight in a kame; 22% dw in cryoconite) and nutrients (nitrogen up to 0.4% dw, phosphorus up to 0.8% dw) were determined in the samples. In cryoconite sediment, the highest numbers of bacteria, cyanobacteria, and algae were found, whereas relatively low microbial abundances were recorded in moraines and kames. Cyanobacterial cells were significantly more abundant than microalgal ones in cryoconite and supraglacial kames. Different species of the cyanobacterial genus Leptolyngbya were by far the most represented in all samples, and cyanobacteria of the genera Phormidium and Nostoc prevailed in cultures isolated from cryoconite samples. These species are considered opportunistic organisms with wide ecological valency and strong colonizing potential rather than glacial specialists. Statistical analyses suggest that fine sediment with higher water content is the most suitable condition for bacteria, cyanobacteria, and algae. Also, a positive impact of lower pH on microbial growth was found. The fate of a microbial cell deposited on the glacier surface seems therefore predetermined by the physical and chemical factors such as texture of sediment and water content rather than spatial factors or the origin of sediment.

• MeSH
• Ecosystem MeSH
• Eukaryota growth & development   MeSH
• Geologic Sediments microbiology   MeSH
• Ice Cover microbiology   MeSH
• Environmental Microbiology MeSH
• Cyanobacteria growth & development   MeSH
• Geography MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Svalbard MeSH