Latest news on the red tide in Knysna
13 January 2014
Sample results: Cells no longer active
Additional water samples collected from three areas in the Knysna estuary over the weekend subsequent to an issued warning last week have indicated the bloom has degraded significantly. ‘The cells are no longer active’ says Professor Brian Allanson of the Knysna Basin Project.
The presence of phytoplankton bloom from previous samples, led to authorities cautioning against the collection of shellfish from the Knysna estuary.
SANParks has requested the public to remain cautious in the event of any possible reoccurrence.
What are these phytonplankton organisms?
According to a Marine and Coastal Management Guideline from the Department of Environmental Affairs, Phytonplankton are ‘microscopic, single-celled organisms that float in the sea. They are able to photosynthesise and form the basis of food chains in the oceans. There are three types of red tide organisms, dinoflagellates, diatoms and ciliates.’
Dinoflagellates usually lie dormant on the seabed until they are lifted to the surface during upwelling where the ideal conditions of temperature and light trigger their germination.
Paralytic Shellfish Poisoning (PSP), which produces toxins that disrupt normal nerve functions, can be associated closely with dinoflagellate. Symptoms of PSP appear anytime between one and five hours after eating contaminated seafood.
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