Microbial Biodiversity of Thermophilic Communities in Hot Mineral Soils of Tramway Ridge, Mt. Erebus, Antarctica

• Main Author: Soo, Rochelle M.
• Format: Thesis
• Language: English
• Published: The University of Waikato 2007
• Subjects: Tramway Ridge; Mt Erebus; Bacteria; Archaea; Physico-chemical; culture-independent; Mount Erebus; Antarc*; Antarctica
• Online Access: https://hdl.handle.net/10289/2441

Only a few studies have looked at microbial biogeography in soils and whether microorganisms are endemic to an area is still debatable. Tramway Ridge, a geothermal area on Mount Erebus, Antarctica, provides a unique opportunity due to its isolation and extreme conditions to explore the possibilities of microbial endemism and to identify novel Bacteria and Archaea. This site was chosen for a culture-independent study with a preliminary culturing survey for bacterial communities along three temperature gradients (65 C - 2.5'C). In addition, a physico-chemical analysis was undertaken to identify which environmental factors were driving the different diversity along the transects. An automated rRNA intergenic spacer analysis (ARISA) was used to assess the diversity across the transects using Bacteria and Cyanobacteria-specific primers and results showed that temperature and pH were the main drivers for these communities. Due to its unique physico-chemical and ARISA profile, a hot temperature site (T-3A, 65'C) was chosen for further investigation by bacterial and archaeal 16S rDNA clone libraries. Unique rDNA types among the 78 bacterial and 83 archaeal clones were identified by restriction fragment length polymophisms and 18 bacterial and 5 archaeal operational taxonomic units (gt97% identity) were observed. All of the bacterial sequences were deeply branching and loosely affiliated with other recognised bacterial divisions, with 40% of the sequences not affiliated to any genus. The archaeal clones were found to be deep-branching and sequences clustered together within the Crenarcaheota. In addition, two strains of Bacilli were isolated. The novel microorganisms show that the Tramway Ridge communities are unique from organisms found in other environments and show that quotEverything is (not) everywherequot.