DSpace
 

Researchspace >
General science, engineering & technology >
General science, engineering & technology >
General science, engineering & technology >

Please use this identifier to cite or link to this item: http://hdl.handle.net/10204/5094

Title: Use of remote sensing and molecular markers to detect toxic cyanobacterial hyperscum crust: A case study on Lake Hartbeespoort, South Africa
Authors: Oberholster, PJ
Botha, AM
Keywords: Hyperscum crust
Reverse-transcription PCR
McyA levels
Microcystin
Satellite imaging
Cyanobacteria
Issue Date: Dec-2010
Publisher: Academic Journals
Citation: Oberholster, PJ, and 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(51), pp 8791-8799
Series/Report no.: Workflow;5489
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.
Description: Copyright: 2010 Academic Journals. This is a post print version of the work. The definitive version is published in the African Journal of Biotechnology, Vol. 9(51), pp 8791-8799
URI: http://www.academicjournals.org/AJB/abstracts/abs2010/20Dec/Oberholster%20and%20Botha.htm
http://hdl.handle.net/10204/5094
ISSN: 1684-5315
Appears in Collections:Accessibility research
General science, engineering & technology

Files in This Item:

File Description SizeFormat
Oberholster2_2010.pdf1.92 MBAdobe PDFView/Open
View Statistics

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

 

Valid XHTML 1.0! DSpace Software Copyright © 2002-2010  Duraspace - Feedback