Illuminating Creatures – what makes them glow?
How and why some creatures glow is truly fascinating. Sadly, studying this phenomenon has proven difficult for marine biologists, making illuminating creatures seem even more mysterious and magical. Although many marine species glow, they don’t all glow in the same way and there are actually two main causes for this phenomenon; bioluminescence and bioflourescence.
Bioluminescence is when creatures actually emit light, either thanks to chemicals in their body, or to bacteria living on their skin.
For the creatures that glow because of chemical reactions within their bodies, the source of their wonderful glow is thanks to two substances called luciferin and luciferase. When these two substances combine to form a light-emitting compound. This type of reaction is similar to what happens when you crack a glow stick to light it up.
Research by marine biologists estimates that up to 90% of species living in the deep sea – thousands of meters down where sunlight can’t reach – are bioluminescent. Deep-sea fish in particular use this clever trick to attract prey and locate food, whereas glowing creatures in shallower waters use bioluminescence as a defense mechanism. Not much is known about bioluminescence in marine creatures as they lose their ability to glow when captured, making it difficult to study.
It’s estimated that over 180 species of fish and sharks are capable of bioflourescence. Unlike bioluminescence, bioflourescence isn’t a chemical reaction but the absorption and reemission of existing light. Creatures do this by absorbing blue light and emitting it as red, orange or green – all colours which travel well underwater and are a stark contrast to the usual blue hue of the sea.
What this means is that biofluorescence requires an external source of light, which means that only species that are exposed to sunlight can exhibit this trait – this is why deep sea creatures are bioluminescent rather than biofluorescent. According to marine biologists, this type of natural glow is used mainly for camouflage, communication and attracting mates.
Illuminating Creatures at SEA LIFE Blackpool
If you want to learn more about glow in dark sea creatures, then you’re in luck. In our Octo-Glow Explorers Event you’ll learn all about how different glowing creatures use this ability to communicate, attract mates, and hide from predators.
Now that you’re an expert on glowing marine creatures, why not take a trip to the rainforest and discover the importance of insects?