Use of remote sensing and molecular markers to detect toxic cyanobacterial hyperscum crust : A case study on Lake Hartbeespoort, South Africa

Show simple item record

dc.contributor.author Oberholster, Paul Johan
dc.contributor.author Botha, Anna-Maria
dc.date.accessioned 2011-02-10T06:43:34Z
dc.date.available 2011-02-10T06:43:34Z
dc.date.issued 2010-12
dc.description.abstract In this study, we monitored the formation of cyanobacterial hyperscum and crust formation in Lake Hartbeespoort using satellite images and ground monitoring. The hyperscum that formed near the reservoir wall was characterised by a distinctive white surface layer of crust. Hyperscum is the result of exposure of the cells to high radiation, inflicting irreversible damage to the genetic constitution of the upper layer of Microcystis aeruginosa cells. Under the 3 mm thick layer of crust, dark (<0.93 μmol of photons m-2s-1) anaerobic conditions (0.4 mg/l, 3% saturation) prevailed with high levels of microcystin (12,300 μg/l) in the absence of sunlight irradiation and photolysis by UV light. Real time polymerase chain reaction (PCR) analysis indicated low levels of transcription of the mcyA, mcyB and mcyD genes which are responsible for synthesis of cyanotoxins under these low light intensity conditions. At other sampling sites where cyanobacterial scum occurred and hyperscum crust was absent, only the mcyB and mcyD genes were transcribed. A plausible explanation for the transcription of the mcyA gene in the hyperscum and not at the other sampling sites, was the presence of environmental stress-inducing factors, e.g. low light intensity (0.93 μmol of photon m-2 s-1) and pH 6.1. At the sampling site where no cyanobacterial scum was visible on the satellite images, low cell abundance (2.4 x 104 μg/l) and chlorophyll a (12.2 μg/l) was measured in comparison with sites where cyanobacterial scum was visible on the satellite images. en_US
dc.identifier.citation Oberholster, PJ & Botha, AM 2010, 'Use of remote sensing and molecular markers to detect toxic cyanobacterial hyperscum crust: A case study on Lake Hartbeespoort, South Africa', African Journal of Biotechnology, vol. 9, no. 51, pp. 8791-8799. [http://www.academicjournals.org/AJB] en_US
dc.identifier.issn 1684-5315
dc.identifier.uri http://hdl.handle.net/2263/15851
dc.language.iso en en_US
dc.publisher Academic Journals en_US
dc.rights © 2010 Academic Journals en_US
dc.subject Hyperscum crust en_US
dc.subject Reverse-transcription PCR en_US
dc.subject McyA levels en_US
dc.subject Microcystin en_US
dc.subject Satellite imaging en_US
dc.subject Cyanobacteria en_US
dc.subject.lcsh Cyanobacteria en
dc.subject.lcsh Cyanobacterial toxins en
dc.title Use of remote sensing and molecular markers to detect toxic cyanobacterial hyperscum crust : A case study on Lake Hartbeespoort, South Africa en_US
dc.type Article en_US


Files in this item

This item appears in the following Collection(s)

Show simple item record