Date of Award

2010

Thesis Type

Masters

Document Type

Dissertation

Divisions

Faculty of Science

Department

Institute of Biological Sciences

Institution

Universiti Malaya

Abstract

Bacterial diversity in soil and sediment samples from eighteen sites in and around Dasan Station, Ny-Ålesund, Norway was analyzed using Denaturing Gradient Gel Electrophoresis (DGGE), and was correlated with the environmental variables. Samples analysed included terrestrial soils, beach soil, periglacier soils, inland lake bank sediments, melt lake sediments, and marine sediments. Spearman rank order correlation showed significant correlations (P = 0.001) between conductivity (r = 0.470) and pH (r = 0.294) with the bacterial diversity. Soil from the tundra site (sample 17) appeared to have the most diverse bacterial community while inland lake bank sediment from the freshwater site (sample 35) showed the least diverse bacterial community. Non-metric multidimensional scaling plots (nMDS) and Hierarchical cluster analysis showed that the bacterial community structure was eventually clustered into two groups: non-marine and marine samples. Out of 28 DGGE bands that were sequenced, nine sequences were related to unclassified bacteria, four sequences each were related to Bacteroidetes and β-proteobacteria, two each were related to Cyanobacteria, Firmicutes and Fusobacteria, and one each was related to Acidobacteria, ε-proteobacteria, δ-proteobacteria, Fibrobacteres and Nitrospira. Despite unclassified bacteria, Bacteroidetes were dominant in marine (22.45%) and beach samples (28.55 %) while β-proteobacteria were the dominant group in terrestrial (15.85 %) and melt lake (21.05 %) samples. On the other hand, the inland lake bank samples were dominated (14.81 %) by Cyanobacteria, Fibrobacteres, Firmicutes and β-proteobacteria. Where as, the periglacier samples were dominated (21.05 %) by Bacteroidetes and β-proteobacteria. Phylogenetic analysis of sequences of well-defined DGGE bands displayed four distinct clades, which consisted of (i) Bacteroidetes and Cyanobacteria; (ii) Firmicutes, Nitrospira, Fibrobacteres, Acidobacteria, ε-proteobacteria and δ-proteobacteria; (iii) β-proteobacteria; and (iv) Fusobacteria. There was a distinct clade of uncultured representatives that were not closely related to any known GenBank sequences. This probably represent a potential gene pool of novel species which yet to be cultured or identified.

Initial

khm

Additional Information

Dissertation (M.A.) – Faculty of Science, Universiti Malaya, 2010.

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