Algae which could be harmful to humans has been discovered on three beaches in Cornwall.
They are believed to have been blown onshore by the heavy winds recently brought by Storm Ellen.
They were found at Poldhu and Church Cove, on the Lizard Peninsula, as well as at Portwrinkle, on Friday and Saturday.
Phytoplankton were also discovered on the beaches. They are microscopic plant-like organisms that live in water. They have a critical purpose as they generate half of the atmosphere’s oxygen and are the base of the food chain in the oceans.
They are usually too small to be seen, however can look like discoloration of the water when present in high numbers.
The Environment Agency (EA) attended all three beaches and carried out water quality checks over the past few days.
A spokesperson for the EA told BBC Radio Cornwall: “We sent our officers to investigate the cause of this over the weekend. We tested the rivers for any pollution coming from the rivers, we looked at what was coming from the sea and the most likely source of this is that this is due to marine algae.
“This time of year, the sea is really warm. A bit like the growth of plants in our gardens, you get lots of growths of algae so tiny bits of seaweed and microscopic plants in the ocean that are called phytoplankton and they grow in the summer in the warm water. They can get blown on shore when you get really rough seas and they can look like brown deposits.”
The EA advised people against swimming on Saturday and Sunday, as algae can do harm to humans.
“Most is non-toxic, but it can be harmful so it’s best to assume it is and then we advise against bathing,” the spokesperson continued. “It depends on the type, but some organisms can produce toxins. It can be very toxic, most likely not. The most likely harmful effect could be skin irritation. People can have reactions to it. But in very, very extreme cases it can be very dangerous because of toxins caused by bacteria.”
According to the EA’s latest checks, the sea is now safe to bathe in.
“There is no further source of algae onto the beaches, the algae that had blown on shore during Friday and Saturday had broken down in the sun and the wind,” the spokesperson added. “We’re no longer advising against bathing.”
Earlier this year, in June, NASA discovered an unexpectedly large and intense bloom of phytoplankton off the coast of Cornwall.
The space agency shared a breathtaking satellite picture of the area, showing large swathes of bright blue ocean all around Cornwall.
It wrote: “NASA wrote: “Spring and early summer 2020 brought unusually clear skies and persistent, unseasonable heat to northwestern Europe. Those conditions likely set the stage for large and persistent blooms of phytoplankton in the waters around the United Kingdom and Ireland.
“On June 23, 2020, the Operational Land Imager (OLI) on Landsat 8 acquired natural-color imagery of a massive phytoplankton bloom off the coast of southwestern England.
“The milky, light-colored waters are probably filled with coccolithophores, which have calcium carbonate plates that appear chalky white when amassed in great numbers. Greener waters may be rich with diatoms or suspended sediment. It is impossible to know for sure without taking direct water samples. The brightness of the color may reflect the density of the phytoplankton, while the various swirls and shapes trace the intricate movements of currents, eddies, and tides.”
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