Ostreopsis: Is the presence of this algae on the Basque Coast a cause for concern?

LET’S LIST 3 CAUSES OF OSTREOPSIS ALGAE GROWTH

1- The primary cause of algae growth is high water temperature: Ostreopsis algae thrive when the water temperature reaches 20°C or higher. Climate fluctuations can contribute to their proliferation.

2- Specific environmental conditions must be present: These include low water circulation and high light levels, which can promote algae growth through photosynthesis. In other words, light energy is stored in the chemical bonds of a well-known compound: glucose. This promotes the growth of algae.

3- Spread from the Mediterranean: Ostreopsis algae, native to tropical and Mediterranean regions, have begun to spread into the Atlantic and are now reaching the French coast, including the Basque Coast.

WHAT ARE THE IMPACTS ON HEALTH AND THE ENVIRONMENT?

1- Human health concerns: Ostreopsis algae can cause symptoms such as headaches, nausea, skin irritation, stomach upset, and respiratory problems in people exposed to them for too long. The National Health Safety Agency recommends preventive measures for professionals working near beaches.

2- Beach Closures: Due to the presence of Ostreopsis algae, some beaches along the Basque coast have had to be closed to ensure the safety of swimmers and visitors.

3- Impact on the marine ecosystem: Ostreopsis algae can have harmful effects on organisms

Marine organisms, such as fish and crustaceans, disrupt the ecological balance of coastal ecosystems.

WHAT SOLUTIONS ARE AVAILABLE TO COMBAT THESE ALGAE AND PREVENT RISKS?

Strengthening Monitoring: It is essential to strengthen monitoring of the presence and growth of Ostreopsis algae on all beaches where water activities take place, including swimming, surfing, and sailing. Regular and frequent samples should be collected to assess the presence of the algae.

Awareness and Education: There is a need to raise public awareness about the risks associated with Ostreopsis algae. Local authorities and environmental organizations such as Surf Rider can play a key role in informing people about symptoms, precautions to take, and preventive measures.

Reducing coastal pollution: It is important to reduce sources of pollution, including wastewater discharges, excessive nutrient inputs from agriculture, and chemicals that can promote algae growth. Beach cleanup and waste collection initiatives, such as those led by the Magic Surf School, can help reduce coastal pollution.

Don’t panic! To find out if it’s safe to go for a swim, just look at the flags—specifically, look for the purple flag. When toxin levels exceed acceptable thresholds, local authorities take measures to protect the public by banning swimming and raising the purple flag. Ostreopsis algae have already caused beach closures in Anglet, Biarritz, and Saint-Jean-de-Luz.

An alternative to swimming: if you see purple flags during your vacation in the Basque Country, you can always take the opportunity to explore the area by bike. The Vélodyssée offers hundreds of kilometers of bike paths along the coast. Whether you choose a traditional bike for the more adventurous or an e-bike, the experience will be a wonderful way to discover the region. Feel free to visit our Marty Bike Rental website to see the equipment we can provide.

See you soon on the waves or on the road!

Marty