Distribution and characterization of bacterial communities in diverse Antarctic ecosystems by high-throughput sequencing

• Main Author: Tytgat, Bjorn
• Other Authors: Willems, Anne, Verleyen, Elie
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Ghent University. Faculty of Sciences 2016
• Subjects: Biology and Life Sciences; Antarctic; The Antarctic; Antarc*; Antarctica
• Online Access: https://biblio.ugent.be/publication/7248976; http://hdl.handle.net/1854/LU-7248976; https://biblio.ugent.be/publication/7248976/file/7249031

Geological events and historical climate changes have eliminated or reduced most life in Antarctica to mainly microbial organisms in relatively simple communities. Due to its exceptional location, millennia long isolations and extreme climatic conditions, the continent offers a spectacular and unique background for fundamental scientific research and the testing of hypotheses. Notwithstanding the fact that Antarctica is still considered by many to be one of the last pristine environments on Earth, it is not only threatened by climate change, which particularly has severe effects on parts of West and Maritime Antarctica, but also by an ever increasing number of tourists and even scientists themselves. Studies on Antarctic biota are relatively scarce, and despite the fact that bacteria are fundamental to the Antarctic ecosystems, only a minority of the studies focus on these organisms. This results in a lacuna in the knowledge about the diversity, distribution and functioning of and the relationships between these organisms under the extreme Antarctic conditions. The recent advent of High-throughput sequencing (HTS) applications enables to sequence millions of DNA-fragments in a very short time, allowing us to visualise bacterial communities at a very high resolution, without the necessity for prior isolation of the organisms. In this PhD-study, we have applied some of these new technologies in order to investigate the bacterial diversity of different habitats throughout the Antarctic. In a first study (Chapter 2), we have compared the results obtained by pyrosequencing and compared these with the results of a previous isolation campaign. As expected, a much larger diversity of bacteria were found with pyrosequencing. While five bacterial phyla were recovered by cultivation, this was the case for 22 phyla with the NGS-approach, and a large amount of unknown diversity was evident. At the same time, it became clear that also the part of the 16S rRNA gene that was sequenced had an impact on the perceived diversity, ...