The Andalusian coast may soon offer residents and tourists a rare and beautiful spectacle. This is the natural phenomenon known as “mar de ardora,” when the water near the shore begins to glow with a neon-blue light. One of the beaches in the province of Cádiz is considered an ideal spot to observe this phenomenon, which transforms the nighttime landscape into a scene from a science fiction movie.
The cause of this magical glow is bioluminescence—the ability of living organisms to emit light. In this case, the main ‘culprits’ are microscopic organisms that make up plankton, in particular the dinoflagellate Noctiluca scintillans. As a result of a chemical reaction triggered by water movement, such as waves or even a simple touch, these microorganisms emit bright blue flashes. For them, it is a natural defense mechanism against predators and a way to attract prey.
Although bioluminescent beaches are often associated with exotic destinations like the Maldives, this wonder can also be seen in Spain. The beach in the municipality of La Linea de la Concepcion in the province of Cádiz has been attracting nature lovers and photographers for several years. The calm and warm waters of this bay during the summer create a favorable environment for the accumulation of plankton responsible for the glow.
To witness the ‘Ardor Sea’ in all its glory, several factors must align. The most important is minimal light pollution. For this reason, the ideal time for observation is during the new moon phase. The next new moon is expected this Saturday, August 23, 2025, which greatly increases the chances of seeing the glow. The complete absence of moonlight in the sky allows even the faintest flashes in the water to be seen.
Besides the lunar phase, weather plays an important role as well. It is believed that the eastern wind, levante, helps concentrate plankton along the shore, while the western wind, poniente, can disperse it. Another daytime sign to watch for is the appearance of orange or reddish patches on the water’s surface or along the surf line. These are clusters of Noctiluca scintillans algae, which after nightfall will turn into a scattering of glowing lights.
In previous years, social networks were filled with striking photos and videos from this beach, making it one of the most sought-after places to visit at the end of summer. Those planning to go ‘hunting’ for glowing waves this coming weekend can only hope for a bit of luck and the right natural conditions.
