Why the sea may be brown and smelly... it’s algae!

There have been significant algal blooms along a stretch of the South Devon coast for several weeks now. This is a common and natural phenomenon, which develops well in very warm weather, say the Environmental Health team at East Devon District Council. 

The algae have been identified by the Environment Agency, who advise that they are essentially harmless. It is safe to swim in the sea when the bloom is present, but often people choose not to because it has a slimy feel and causes the water to be somewhat murky and odorous.  Many people in Sidmouth particularly noticed a strong smell from it all over the town last week. 

The same situation has occurred elsewhere along the coast – at least as far as Torbay. Advice to people who come into contact with the algae is to avoid swallowing the water, rinse off after swimming, and to wash hands and faces before eating and drinking.  I have attached some information provided by the Environment Agency if you require any more detail.

Recent sampling by the Environment Agency has revealed that a bloom of the marine microalgal species Phaeocystis is present at several bathing waters. Analysis of algal samples collected show they contain large numbers of Phaeocystis which is an aesthetic nuisance species rather than harmful/toxic.

Currently the bloom is widespread across most of the south coast of Devon and Cornwall and is growing in terms of the number of incidents being reported. The bloom can appear as a brown frothy scum which onshore winds can whip up into a brown foam. Once onshore it breaks down into a brown slime which can smell similar to sewage. It is expected that due to the settled weather at the moment these blooms will persist for a while longer.