Am currently reading The Wild Places by Robert Macfarlane, and came across the story below (one that first requires understanding of something marine biological).
It is now understood that marine phosphorescence is a consequence of the build-up in the water of minute bioluminescent organisms: dinoflagellate algae and plankton. By processes not entirely understood, these simple creatures ignite into light when jostled. They convert the energy of movement into the energy of radiance.
There have been few sightings of marine phosphorescence, and here’s a story of one of those sightings.
In 2004, a father and son were sailing in the Gulf of Mexico when their yacht was capsized by a gust of wind, sixty miles offshore. They clung to the hull, as it was carried on the powerful currents of the Gulf. After night fell, the water became rich with phosphorescence, and the air was filled with a high discordant music, made of many different notes: the siren song of dolphins. The drifting pair also saw that they were at the centre of two rough circles of phosphorescence, one turning within the other. The inner circle of light, they realised, was a ring of dolphins, swimming round the upturned boat, and the outer circle was a ring of sharks, swimming around the dolphins. The dolphins were protecting the father and his son, keeping the sharks from them.
– both quotes from Robert Macfarlane’s The Wild Places (pp.41-2)