Discoloured water caused by microalgae on Nerja´s El Playazo. / E. CABEZAS

Harmless orange algae returns to Axarquía coastline

The natural phenomenon, caused by a sudden change in the temperature of the water, has also happened in previous years on the Costa del Sol

Eugenio Cabezas

Orange patches have reappeared in the Axarquía's coastal waters this week. Caused by the proliferation of a type of microalgae, it is a natural and harmless phenomenon. However, the ugly appearance and large spread of them, from Nerja to Rincón de la Victoria, have meant that many bathers have complained about their presence.

Servimar, the company which cleans the bathing waters on the eastern coast of the Costa del Sol, had a busy time on Wednesday dissolving the patches from its fleet of boats. Company manager, Manuel Rivas, told SUR: "We have not been able to cope with so many calls, from Rincón de la Victoria to Nerja".

Aula del Mar biologists Jesús Bellido and Juan Jesús Martín told SUR that this is a "natural and harmless" phenomenon, as was previously confirmed after analyses in 2017 by Emasa.

"It is typical of the end of spring and the beginning of summer, due to a sudden change in sea temperature, as has happened in the last few days. It has nothing to do with the spawning of the anchovy, nor are they roe, they are microalgae, brown algae, a type of dinoflagellate organisms, which reproduce suddenly," Martín said.

This accumulation of microalgae can colour the surface of the sea with an orangey tone and a slightly oily appearance. Bellido added that "sometimes it is caused by pollution". The previous major episode of these orange patches on the Malaga coastline occurred in March 2021 in Malaga port.