Abstract:The simple filamentous cyanobacterial genus Geitlerinema is heterogeneous. At least two distinct phylogenetic clades can be derived from the set of most common freshwater Geitlerinema species. Our revision is based on the original description of the type species G. splendidum aka Oscillatoria spendida and on molecular sequencing of morphologically relevant strains. The revised Geitlerinema contains only one species according to morphological similarity with its original description. Consequently, the majority of other freshwater species inferred from molecular sequencing of 16S rRNA gene and 16S-23S ITS analysis (related both genetically and morphologically to G. pseudacutissimum) must be classified as a special taxon on the generic level. The name Anagnostidinema is proposed for this genus, which was selected in memory of the prominent late cyanobacterial specialist Konstantinos Anagnostidis. The genetic position, short review and characteristics of the newly defined genus Anagnostidinema is presented in this paper. The taxonomy of the rest of species (including the marine taxa), which are currently unable to be classified taxonomically with certainty, remain to be resolved in future studies.

Very thin filamentous cyanobacteria are ubiquitous in a wide range of environments. For many years they were traditionally studied according to their morphological properties only. With the introduction of additional taxonomic methods (cytomorphological analyses, molecular sequencing, exact ecological studies, better data about phytogeographical distribution), traditional genera such as Leptolyngbya and Phormidium were found to be polyphyletic. Phormidesmis belonged to a newly formed genus that was supposed to explain the variability of such very thin simple filamentous cyanobacteria. However, even after definition of Phormidesmis based on distinct cytomorphological and phylogenetic traits, the variability within this genus remained unresolved. Here we analyzed 26 Phormidesmis strains to describe the variability within this genus, classified two new species (P. arctica and P. communis) and transferred Leptolyngbya nigrescens into P. nigrescens. A tabular review of Phormidesmis species is included. The diacritical features of all these species are: width up to 1–4 µm, barrel-shaped cells, which can be shorter or slightly longer than wide, with apparent constrictions at the cross-walls. Our study shows that Phormidesmis is a morphologically and genetically well-defined genus with a global distribution. A newly described genus Leptodesmis has significant morphological similarities both with Phormidesmis and Leptolyngbya, however with intermediate phylogenetic position with significant divergence in 16S rRNA gene. Leptodesmis is cryptic both to Phormidesmis and Leptolyngbya. In the initial part of the life cycle resembles Leptolyngbya, the appearance of older trichomes change to Phormidesmis like morphology.

The diversity of cyanobacteria along the Alaskan North Slope was investigated. We isolated and cultivated 57 strains of cyanobacteria and sequenced a section of their rRNA operon containing a fragment of the 16S rRNA gene. Here, we describe 17 found species belonging mainly to families Coleofasciculaceae, Microcoleaceae, Oculatellaceae, Leptolyngbyaceae and to the order Synechococcales. In pursuing a conservative polyphasic approach, we utilized suggested thresholds in 16S rRNA gene differences in parallel with morphological differences between new and already described taxa for the description of new species and genera. Based on a combination of morphological, molecular and ecological analysis of collected and cultured strains we describe two genera Gibliniella and Shackletoniella as well as six cyanobacterial species; Cephalothrix alaskaensis, Tildeniella alaskaensis, Pseudophormidium americanum, Leptodesmis alaskaensis, Albertania alaskaensis and Nodosilinea alaskaensis. Here, a polyphasic approach was used to identify eight novel and nine established cyanobacterial taxa from a previously non–investigated region that uncovered a high degree of biodiversity in extreme polar environments.

The bone remnants of sea mammals are frequently dispersed everywhere in coastal areas of Svalbard Archipelago represent aspecific natural habitat which is colonized by aeroterrestrial microscopic algae. Such bone habitat might be considered an analogue to stone substrates. However, bone habitats are not included in ecological studies of polar region. In the present study, thorough observations were made on some algal strains isolated to laboratory cultures. They included two green algal species Pseudodictyo-chloris multinucleata and Tetracystis pulchra, as well as two stramenopile algal species Heterococcus papillosus and Xanthonema debile. All these taxa are new additions to the Svalbard flora.

Substrates created by human have a significant impact on Arctic terrestrial environment. These substrates are new potential niche for microbial biota, which may have several essential chemical agents supporting microbial growth. Wood, concrete, brick, ceramic and other different building materials, which have been introduced by human in this isolated environment, are colonized with terrestrial and aero-terrestrial microorganisms living in the natural niches near the substrates like soil, rocks, etc., but these materials newlyintroduced to Svalbard terrestrial ecosystems can also work as vectors for invasion of new species into the environment. We have collected different types of artificial substrates mainly in the region of Petuniabukta bay and studied the species composition of microbial phototrophs living there. A total of 25 taxa of cyanobacteria and algae were documented on different types of substrates like brick walls, concrete, glass, iron, wood and plastic. A commonality in species diversity was observed with similar substrates in temperate climatic regions. Fottea stichococcoides, Sphaerococcomyxa olivacea, Polysphaera composita and Diplosphaera chodatii were first time recorded from Svalbard Archipelago.