Rhodotorula svalbardensis sp. nov., a novel yeast species isolated from cryoconite holes of Ny-Ålesund,Arctic

A psychrophilic yeast species was isolated from glacier cryoconite holes of Svalbard. Nucleotide sequences of the strains were studied using D1/D2 domain, ITS region and partial sequences of mitochondrial cytochrome b gene. The strains belonged to a clade of psychrophilic yeasts, but showed marked differences from related species in the D1/D2 domain and biochemical characters. Effects of temperature, salt and media on growth of the cultures were also studied. Screening of the cultures for amylase, cellulase, protease, lipase, urease and catalase activities was carried out. The strains expressed high amylase and lipase activities. Freeze tolerance ability of the isolates indicated the formation of unique hexagonal ice crystal structures due to presence of ‘antifreeze proteins’ (AFPs). FAME analysis of cultures showed a unique trend of increase in unsaturated fatty acids with decrease in temperature. The major fatty acids recorded were oleic acid, linoleic acid, linolenic acid, palmitic acid, stearic acid, myristic acid and pentadecanoic acid. Based on sequence data and, physiological and morphological properties of the strains, we propose a novel species, Rhodotorula svalbardensis and designate strains MLB-I (CCP-II) and CRY-YB-1 (CBS 12863, JCM 19699, JCM 19700, MTCC 10952) as its type strains (Etymology: sval.bar.den′sis. N.L. fem. adj. svalbardensis pertaining to Svalbard).     

The Fish Trail Undichna quadrisulcata isp. nov. from the Eocene of Spitsbergen

Abstract

Undichna quadrisulcata isp. nov. is described from the Eocene of Spitsbergen, where it occurs together with xiphosuran (horseshoe crabs) traces in upper shoreface to foreshore deltaic sandstone. This is the first record of a marine (deltaic) Undichna from the Eocene. The trail consists of two or three pairs of paralleling sinusoidal grooves (in epirelief) or ridges (in hyporelief). Previous records of this trace fossil from the Carboniferous and Permian were assigned to U. insolentia Anderson, 1976 Anderson, A. M. 1976. Fish trails from the early Permian of South Africa. Palaeontology 19(2): 397–409. [Google Scholar], which, however, comprises a more complex pattern. The repeated occurrence of U. quadrisulcata isp. nov. in the Carboniferous, Permian, Triassic and Eocene, independent from U. insolentia, justifies its own ichnospecies name and suggests a different kind of producer. U. quadrisulcata isp. nov. is interpreted as a fish trail, probably produced by a representative of Amiiformes (actinopterygian, ray-finned fish) or coelacanth fish.     

Molecular and morphological diversity of Zygnema and Zygnemopsis (Zygnematophyceae,Streptophyta) from Svalbard (High Arctic)

ABSTRACT

Filamentous conjugating green microalgae (Zygnematophyceae, Streptophyta) belong to the most common primary producers in polar hydro-terrestrial environments such as meltwater streamlets and shallow pools. The mats formed by these organisms are mostly composed of sterile filaments with Zygnema morphology, but the extent of their diversity remains unknown. Traditional taxonomy of this group is based on reproductive morphology, but sexual reproduction (conjugation and formation of resistant zygospores) is very rare in extreme conditions. In the present study we gave the first record of zygospore formation in Svalbard field samples, and identified conjugating filaments as Zygnemopsis lamellata and Zygnema cf. calosporum. We applied molecular phylogeny to study genetic diversity of sterile Zygnema filaments from Svalbard in the High Arctic. Based on analysis of 143 rbcL sequences, we revealed a surprisingly high molecular diversity: 12 Arctic Zygnema genotypes and one Zygnemopsis genotype were found. In addition, we characterized individual Arctic genotypes based on cell width and chloroplast morphology using light and confocal laser scanning microscopy. Our findings highlight the importance of a molecular approach when working with sterile filamentous Zygnematophyceae, as hidden diversity might be very beneficial for adaptation to harsh environmental conditions, and experimental results could be misinterpreted when hidden diversity is neglected.     

Rumen microbial diversity in Svalbard reindeer, with particular emphasis on methanogenic archaea

Ruminal methanogens, bacteria and ciliate protozoa of Svalbard reindeer grazing natural pastures in October (late fall) and April (late winter) were investigated using molecular-based approaches. The appetite of the Svalbard reindeer peaks in August (summer) and is at its lowest in March (winter). Microbial numbers, quantified by real-time PCR, did not change significantly between October and April, when food intakes are at similar levels, although the numbers of methanogens tended to be higher in October ( P =0.074), and ciliate numbers tended to be higher in April ( P= 0.055). Similarly, no change was detected in the bacterial and protozoal population composition by rRNA gene-based denaturing gradient gel electrophoresis analysis. Dominant methanogens were identified using a 16S rRNA gene library (97 clones) prepared from pooled PCR products from reindeer on October pasture ( n =5). Eleven of the 22 distinct operational taxonomic units (OTUs) generated exhibited a high degree of sequence similarity to methanogens affiliated with Methanobacteriales (eight OTUs), Methanomicrobiales (one OTU) and Methanosarcinales (two OTUs). The remaining 11 OTUs (53% of the clones) were associated with a cluster of uncultivated ruminal archaea. This study has provided important insights into the rumen microbiome of a high-arctic herbivorous animal living under harsh nutritional conditions, and evidence suggesting that host type affects the population size of ruminal methanogens.     

Comprehensive comparisons of three pennate diatoms, Diatoma tenuae, Fragilaria vaucheriae, and Navicula pelliculosa, isolated from summer Arctic reservoirs (Svalbard 79°N), by fine-scale morphology and nuclear 18S ribosomal DNA

Here we report morphological and molecular characteristics of dominant freshwater diatoms in summer Arctic reservoirs of Svalbard (Norway), using four culture isolates, when we collected the samples in the field on 15 August 2005. Analyses of morphology and BLAST searches with 18S rDNA sequences identified them to Diatoma tenue (HYNP006, HYNP013), Navicula pelliculosa (HYNP021), and Fragilaria vaucheriae (HYNP022), respectively. Comparative studies of morphology revealed that the body shapes of the three polar diatoms were nearly identical to the known morphology of each species; however, they were considerably shorter in body length than previously described identical species from other locations. The 18S rDNA sequences of the diatoms were nearly identical to the same species from temperate and other regions. Phylogenetic analysis showed that the polar diatoms each formed a clade with their identical species and genera according to their taxonomic positions. This suggests that the polar diatoms may possess little or no genetic or morphological variation compared to more temperate strains.     

Same parental species, but different taxa: molecular evidence for hybrid origins of the rare endemics Saxifraga opdalensis and S. svalbardensis (Saxifragaceae)

Saxifraga opdolensis was described from Oppdal in southern Norway and hypothesized to have originated as the hybrid S. cernua × rivularis or to have been derived from a S . cernua-like progenitor. We tested these alternative hypotheses using uni- and biparentally inherited molecular markers observed in S. opdalensis and its putative parental species at the type locality: PCR-RFLPs (restriction fragment length polymorphisms in amplified fragments of chloroplast DNA; cpDNA), sequences of the cpDNA intron trnL and the spacer tmL-tmF , and RAPDs (random amplified polymorphic DNAs). The data provided unambiguous support for the hybrid hypothesis. The cpDNA analyses distinguished two well-differentiated chloroplast genomes, one in S. opdalensis and S. rivularis , and another in S. cernua . The majority of the RAPD markers showed distinct additivity in S. opdalensis relative to its postulated parental species. Thus, S. opdalensis has probably originated from a hybrid with S. rivularis as the maternal parent and S. cernua as the paternal parent. We also included S. svalbaardnsis in the present study because previous molecular analyses of Svalbard material have shown that this species had probably also originated as a hybrid between S. cernua and S. rivularis . The chloroplast genome of S. svalbaardnsis was identical to that of S. opdalensis , but the two species differed in many RAF'D markers. Although these two endemics probably have been derived from the same hybrid combination, they are morphologically and genetically distinct and should be referred to separate species. Differences between such independently originated hybrid taxa may result from intraspecific variation in their parental taxa. Saxufraga cernua comprises, for example, several highly divergent evolutionary lineages.     

Building an indicator to characterize the thermal conditions for plant growth on an Arctic archipelago,Svalbard

Plant growth in the Arctic is strictly dependant on thermal conditions. The purpose of our study is therefore to calculating temperature distributions on the Svalbard archipelago at a relatively high spatial resolution. The model is designed to reflect both the length of the growing season and the temperature sum for a given area (i.e. growing degree-days (GDD)). GDD on Svalbard is defined as the cumulative sum of positive mean daily temperatures in the months of June, July and August. The temperature distribution of GDD for the entire archipelago is calculated from both local and regional information. Local information is derived from data collected in a small area in northwestern Spitsbergen (Kongsfjorden) where a network of 45 thermal sensors recorded air temperatures for five years (2001–2005). A local GDD parameter is computed by a linear combination of elevation, valley depth and NDVI (normalized difference vegetation index). Then this local GDD is applied to the whole of Svalbard (GDD1) and refined stepwise by adding environmental variables such as cloud fraction, land surface temperature, sea surface temperature, distance to the ocean and number of snow-free days. Because the official network of climatological stations on Svalbard is not dense enough and sufficiently well-distributed across the archipelago to enable spatial interpolations for four years only (2011–2014), all outputs are statistically evaluated and adjusted using the values recorded at 9 (2011), 12 (2012) and 13 (2013–2014) meteorological stations (GDD_ref) and used as a set of evaluation data. The final model (GDD_mean), which is the mean of the annual models estimated by regression (GDD_est), performs well: the central parts of Spitsbergen, known for its comparatively high temperatures, contrast with the colder northern and eastern parts of the archipelago.