Morphological and phylogenetic diversity of 143 strains belonging to Oscillatoriales with focuson traditional genera Phormidium sensu lato and Microcoleus were studied. The 88 strains of Ph. autumnale, Ph. setchelianum, Ph. subfuscum, Ph. favosum etc., and M. vaginatus confirmed the generic identity with typical Microcoleus Desmazi?res ex Gomont. The necessary nomenclatoric transfers were realized defining the revised genus Microcoleus. Based on phylogeny and morphology the taxonomic revision of the Antarctic species Ph. murrayi (Lyngbya murray West & West) was implemented and the genus Wilmottia was established. The phylogenetic evaluation of morpho-species included in Phormidium group I (Ph. lloydianum and Ph. acuminatum Gomont) preceded the definition of species Oxynema thaianum spec. nova. The biogeography of Antarctic and Arctic strains of M. vaginatus (Ph. autumnale) based on 16S rDNA and ITS (internal transcribed spacer of the 16S rDNA -23SrDNA ribosomal operon) sequences and strain's morphology was evaluated. The comparison of polar and non-polar strains indicated that the Antarctic populations of M. vaginatus remained isolated from time of the isolation of the Antarctica from the Gondwana before ~31?45 Ma, whereas the transport of populations within Arctic is relatively frequent even at the present time. It was shown that the polar strains of M. vaginatus from the north and south polar areas were not identical.

abstract: Biological soil crusts (biocrusts) are topsoil communities of organisms that contribute to soil fertility and erosion resistance in drylands. Anthropogenic disturbances can quickly damage these communities and their natural recovery can take decades. With the development of accelerated restoration strategies in mind, I studied physiological mechanisms controlling the establishment of cyanobacteria in biocrusts, since these photoautotrophs are not just the biocrust pioneer organisms, but also largely responsible for improving key soil attributes such as physical stability, nutrient content, water retention and albedo. I started by determining the cyanobacterial community composition of a variety of biocrust types from deserts in the Southwestern US. I then isolated a large number of cyanobacterial strains from these locations, pedigreed them based on their 16SrRNA gene sequences, and selective representatives that matched the most abundant cyanobacterial field populations. I then developed methodologies for large-scale growth of the selected isolates to produce location-specific and genetically autochthonous inoculum for restoration. I also developed and tested viable methodologies to physiologically harden this inoculum and improve its survival under harsh field conditions. My tests proved that in most cases good viability of the inoculum could be attained under field-like conditions. In parallel, I used molecular ecology approaches to show that the biocrust pioneer, Microcoleus vaginatus, shapes its surrounding heterotrophic microbiome, enriching for a compositionally-differentiated “cyanosphere” that concentrates the nitrogen-fixing function. I proposed that a mutualism based on carbon for nitrogen exchange between M. vaginatus and its cyanosphere creates a consortium that constitutes the true pioneer community enabling the colonization of nitrogen-poor, bare soils. Using the right mixture of photosynthetic and diazotrophic cultures will thus likely help in soil restoration. Additionally, using physiological assays and molecular meta-analyses, I demonstrated that the largest contributors to N2-fixation in late successional biocrusts (three genera of heterocystous cyanobacteria) partition their niche along temperature gradients, and that this can explain their geographic patterns of dominance within biocrusts worldwide. This finding can improve restoration strategies by incorporating climate-matched physiological types in inoculum formulations. In all, this dissertation resulted in the establishment of a comprehensive "cyanobacterial biocrust nursery", that includes a culture collection containing 101 strains, isolation and cultivation methods, inoculum design strategies as well as field conditioning protocols. It constitutes a new interdisciplinary application of microbiology in restoration ecology. / Dissertation/Thesis / Doctoral Dissertation Liberal Studies 2019