According to the Oxford dictionary bioluminescence is the ‘biochemical emission of light by living organisms’. It is a clever mechanism used by organisms to attract mates, find food and to respond to attacks.
About 80% of bioluminescent species live in the deep sea and it is estimated that most species that live 700 meters below sea level can produce their own light.
To produce their own glow-in-the-dark magic trick they use variations of a chemical reaction using three ingredients: an enzyme called luciferase, oxygen and luciferin.
This enzyme allows the oxygen to bond to the organic molecule luciferin. The high-energy molecule that is created releases the energy in the form of light.
These light producing molecules are interestingly good antioxidants and so it was believed that once they were used as such until they were eventually adapted for signalling. This is because as the oxygen content of the sea increased organisms were forced to dive to deeper depths away from the harmful UV radiation. As it was safer down there, the antioxidants were no longer needed to repair the genetic UV radiation damage and the luciferin was somewhat useless until it became the basis of the light producing reaction.
The best time to see this beautiful spectacle is during the warmer summer months when conditions are ideal for the bioluminescent plankton to multiply in blooms through cell division. The warm water makes them abundant as they blanket the water.
The plankton you see are called Dinoflagellates and they are a single-celled organisms. Their Latin name is Pyrondinium bahamense. First discovered in 1906 in the Bahamas, these plankton photosynthesize during the day for energy and then use this energy at night to produce bioluminescence. Phytoplankton such as these produce up to 50% of the world’s oxygen!
Seeing these amazing organisms at work is a rare spectacle in the UK as they prefer much warmer climates in places such as the Maldives. Despite this, in July 2019, the plankton washed up on along the North Wales shores of Penmon Point in Anglesey.
So next time you are walking along a beach at dusk, look out for sea sparkling, it might just be the Dinoflagellates plankton!