Influences of soil properties on archaeal diversity and distribution in the McMurdo Dry Valleys, Antarctica
Richter, I. (2011). Influences of soil properties on archaeal diversity and distribution in the McMurdo Dry Valleys, Antarctica (Thesis, Master of Science (MSc)). University of Waikato, Hamilton, New Zealand. Retrieved from https://hdl.handle.net/10289/5811
Permanent Research Commons link: https://hdl.handle.net/10289/5811
The Antarctic Dry Valleys are characterized by extremely low temperatures, arid conditions, high salinity and virtual absence of plants. Therefore, food webs of these microbially dominated soils are among the simplest on earth making these mineral soils a perfect model to study microbial biogeography. This study aims to characterize the distribution and diversity of Archaea within the Dry Valleys as part of the New Zealand Terrestrial Antarctic Biocomplexity Survey (NZTABS). An international multidisciplinary organization focusing on biotic organisms, community structure and their functional linkage to determine what environmental factors drive biocomplexity. Archaea are so far the least known members of the microbial community with only a few successful attempts at detection indicating a patchy distribution and low diversity. A wide range of soil samples, collected from various sites within the Dry Valleys were analyzed using a suite of genetic approaches. DNA fingerprinting techniques (RFLP, T- RFLP) were applied to examine distribution and diversity of archaeal species living in soils of Miers Valley, Marshall Valley, Garwood Valley and Shangri- La. Detailed analysis of physicochemical differences between mineral soils was undertaken in hope to unveil environmental factors driving distribution and biodiversity of archaeal communities present in these soils. Multivariate statistical analysis and ordination of T- RFLP results and physicochemical data revealed a widespread distribution of Archaea across all three valleys, including Shangri- La. Overall, archaeal diversity was relatively low and most of the archaeal communities were composed in majority of one species affiliated with Crenarchaeota Marine Group 1.1b. Archaeal communities that sustain a relatively high diversity appear to be restricted to high elevation ridge areas and coastal moraines. This variation in diversity may be best explained by differences in moisture availability and availability of carbon and nitrogen in mineral soils that harbour these communities. Conversely, soils that harbour high bacterial diversity and primary producers revealed extremely low abundance of Archaea, possibly even total absence of Archaea in these organic rich soils.
University of Waikato
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