Full Length Research Paper

Linking climate change and progressive eutrophication to incidents of clustered animal mortalities in different geographical regions of South Africa

P. J. Oberholster¹*, A-M. Botha² and J. G. Myburgh³

¹CSIR Natural Resources and the Environment, P. O. Box 395, Pretoria, ZA0001, South Africa.

²Department of Genetics, University of Pretoria, Hillcrest, Pretoria, South Africa, ZA0001, South Africa.

³Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, P/Bag X04, Onderstepoort ZA0110, South Africa.

*Corresponding author. E-mail: poberholster@csir.co.za.

Accepted 17 September, 2009

   Abstract

Cyanobacterial blooms have become an increasing problem in South African freshwater bodies. Since certain species of cyanobacteria are well-known for biosynthesis of potent hepatic and neurotoxins, such blooms can pose a significant threat to the health of animals and humans. The massive proliferation of these organisms in rivers and lakes is largely due to progressive eutrophication. However, a warming trend in the Southern hemisphere, indicated by a threefold increase in the minimum temperature compared to maximum temperature between 1950 and 1990, is likely the cause of the increasing occurrence of toxic cyanobacterial bloom forming species, previously hampered by low water temperatures in different geographical regions of South Africa.

Key words: Climate change, eutrophication, cyanobacterial blooms, animal mortalities, seasonal cycles.