- Title
- Assessment of the microalgal community structure and biomass in surface waterbodies of the Eastern Cape Karoo region earmarked for shale gas exploration
- Creator
- Roussouw, Natasha Kimberlee
- Subject
- Fresh water -- Eastern Cape
- Subject
- Water-supply -- South Africa -- Eastern Cape Water-supply, Rural -- South Africa -- Eastern Cape Constructed wetlands Watershed management
- Date Issued
- 2018
- Date
- 2018
- Type
- Thesis
- Type
- Masters
- Type
- MSc
- Identifier
- http://hdl.handle.net/10948/35234
- Identifier
- vital:33655
- Description
- The Eastern Cape Karoo region of South Africa typically displays low rainfall and high temperatures, which is particularly concerning considering the shale gas exploration/extraction project proposed recently. Almost 90% of the fracking fluid consists of water and with the Karoo region already classified as a water-stressed region, the increased demand for freshwater for fracking could put further pressure on water resources of the region. By understanding the ecological functioning of the lower trophic levels, likely implications for higher trophic levels can be determined, and ultimately, recommendations for mitigation actions can be made. Here, observations aimed at understanding the dynamics of lower trophic levels are presented, that is, the microalgal biomass and assemblage composition within three characteristic surface waterbodies of the region. In addition, the work focuses on the smaller, more dynamic temporary wetland systems typical of this water-scarce region, with the aim of understanding the significance of single species macrophyte cover in relation to the lower trophic levels. Thirty-three waterbodies were sampled (natural depressions = 13, dams = 9, rivers = 11) during November 2014 (austral spring) and April 2015 (austral autumn). Waterbody physico-chemistry, hydro-morphometry, habitat cover and surrounding land-use, as well as microalgal biomass and assemblage composition within each waterbody type were measured. Thirteen natural depression wetlands were sampled during October 2015, December 2015 and March 2016. Once again, waterbody physico-chemistry, microalgal biomass and assemblage composition were measured. However, in addition, Schoenoplectus decipiens macrophyte cover and microalgal (diatom) species composition were also determined. In general, no significant differences in microalgal biomass between the three main waterbody types of the Eastern Cape Karoo region were found; however, the different waterbody types each displayed distinct microalgal assemblage compositions. Also, Schoenoplectus decipiens cover had negligible effects on microalgal biomass and assemblages in the temporary wetlands investigated here. These results suggest that the generalist nature of species occupying these systems allows them to adapt to the ever-changing conditions typical of this region. Ongoing monitoring initiatives considering impending hydraulic fracturing activities should include a comprehensive species-level diversity census, which could further inform management of any impacts associated with this potential disturbance.
- Format
- xiii, 87 leaves
- Format
- Publisher
- Nelson Mandela University
- Publisher
- Faculty of Science
- Language
- English
- Rights
- Nelson Mandela University
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | Natasha Kimberlee Roussouw.pdf | 2 MB | Adobe Acrobat PDF | View Details Download |