Brown Water at Muizenberg Not a Cause for Concern: City of CT
02/02/10
After receiving complaints about the colour of the sea water at Muizenberg, the City has emphasised that this phenomenon is caused by a naturally occurring sea water algae and not because of 'Khayelitsha sewerage' or 'effluent from the waste water treatment works on the Cape Flats' as is often speculated.
The brown colour of the water seen currently from Muizenberg for several kilometres to the east along the False Bay Coastline is caused by the presence of a type of marine diatom (a microscopic type of algae) known as Annaulus. This is a natural phenomenon that occurs at certain times of the year and under certain seasonal and climatic conditions, not only in this part of South Africa, but also in parts of Australia, New Zealand, Hawaii and California.
Onshore winds may play a role in bringing this brown water closer to the shore. There is no danger to swimmers, beach users or surfers from being in contact with this water, as it is not toxic. The diatoms are a source of food for prawns, fish and filter feeding molluscs.
