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>Magister Scientiae - MSc / Antarctica is known for its pristine environments. A variety of unsuitable environmental conditions were once thought to render the continent unsuitable for sustaining life. However, metagenomic data have revealed a wealth of species diversity in a range of biotopes.Hypolithons, photosynthetic communities which live under translucent rocks in climatically extreme environments, are an important input source for both carbon (C) and nitrogen (N) in this hyperarid desert environment. Microbial contribution to biogeochemical cycling resulting in fixation of both C and N remains poorly understood. Moreover, there is a reported close interplay between both cycles, with nitrogen being reported to be a limiting factor in carbon assimilation.In this study the diversity of C and N fixing organisms was investigated by using the cbbL and nifH genes as phylogenetic and functional markers. High Molecular weight metagenomic DNA and RNA was extracted from hypolithons. PCR amplification was carried out using cbbL (800 bp for red-like, 1,100 bp for green-like) and nifH (360 bp) gene specific primers.Resultant PCR products were used to construct libraries which were screened for correct sized inserts. Restriction Fragment Length Polymorphism (RFLP) was used to de-replicate clones prior to sequencing. Phylogenetic positions from both clone libraries were established by aligning nucleotide sequences and constructing similarity trees using NJ clustering methods.BLASTn results indicated the presence of previously uncultured organisms which contain cbbL and nifH genes. BLASTn results were characterized by low percentages of maximum identity (typically <95%), a potential indicator of novel taxa. Sequences from respective libraries clustered with cyanobacteria such as Nostoc, Scytonema, and Tolypothrix and α-, β-, and γ-Proteobacteria such as Azotobacter, Agrobacterium and Mesorhizobium. Generally sequence results indicate a largely homogenous, being dominated by specific taxa. Each group may contain potential keystone species, essential for both biogeochemical cycling in oligotrophic environment.

The impacts of mining are easily observable in the way they alter the terrain of landscapes, displace animals, and increase waste accumulation in an area. An unobservable impact and one that lasts a long time is by radioactive exposure in the environment. Specifically, this is a risk at uranium (U) mine sites which are expanding in number to accommodate the world’s growing energy needs, and even to accommodate weapons manufacturing. This paper analyses the impacts of an abandoned uranium mine on the local environment through measurements of Uranium concentration in soil, plants, and rocks. Transect sampling was used to collect 22 soil samples and 17 plant samples between 5 and 100m of the mine shaft. Uranium concentrations in soil and plant samples, digested with nitric acid, were measured with an Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES), and an X-ray Powder Diffraction (XRD) analysis was used to find the mineral contents of the rock samples. Satellite positions were associated with each sample, which allowed an effective spatial analysis of the Uranium concentration values. U values in soil ranged from 0 to 5.291ppm, with mean concentrations of 0.710 ppm, and U values in plants ranged from 0.0323 to 0.1121ppm with mean concentrations of 0.0558 ppm. A paired t-test determined that there was no spatial autocorrelation in U concentrations of plants and adjacent soils. The highest U concentration was found closest to the mine, peaking at ~7.3 meters from the mine, and low spatial variability occurs in U concentrations at greater than 10 meters from the mine. In comparison with other mines internationally, U concentrations at this study site were low, which may be indicative of a small operating mine, efficient clean-up, and transport mechanisms of U in desert environments.