Tunisia's glowing blue waves explained as bioluminescent plankton

Spectacular blue waves recently illuminated the shores of Hammam-Lif, Tunisia, capturing the attention of many internet users. The TunSea Association for Participatory Science has provided a scientific explanation for this dazzling display, identifying it as bioluminescence.

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Bioluminescence is the capacity of certain marine organisms to produce their own light through natural chemical reactions occurring within their bodies.

TunSea explained that bioluminescence is the natural ability of certain marine organisms, primarily microscopic plankton like dinoflagellates in the Mediterranean, to generate their own light. This light is produced through internal chemical reactions. The glow is typically activated when the water is disturbed by waves, boats, swimming, or even movement along the shoreline, causing these microorganisms to emit brief blue flashes.

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When the water is agitated by waves, the passage of boats, swimming, or even movements on the shore, these microorganisms undergo mechanical stress that triggers the emission of brief blue glows.

The phenomenon can create breathtaking scenes, with waves appearing to sparkle in the dark, boats leaving luminous trails, and swimmers surrounded by blue halos. TunSea clarified that bioluminescence is distinct from fluorescence, which requires an external light source. Bioluminescence is self-generated and visible in complete darkness. While fluorescence can also occur in the Mediterranean, particularly in corals and jellyfish, bioluminescence is most commonly observed during plankton blooms.

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Unlike fluorescence, which requires an external light source such as the sun or an ultraviolet lamp, bioluminescence is produced directly by living organisms and can be observed in total darkness.

Tunisia has seen sporadic reports of glowing seas along its coastlines, especially during the summer and autumn when marine microorganism concentrations are high. TunSea is actively seeking public assistance, inviting citizens to photograph and report any sightings of luminous waters, including the location, date, and time. These contributions are vital for researchers studying the dynamics of marine ecosystems in the Mediterranean.

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Every observation is a precious piece of data that allows us to better understand the evolution of these natural phenomena and the dynamics of marine ecosystems in the Mediterranean.