“Oh, I see. She’s taken a barnacle, and she’s covered it in bioluminescent algae. As a diversion.” – Tamatoa, Moana
I love that Disney snuck in a quick biology reference to explain the glowing settings in Moana’s Realm of Monsters. To stop Tamatoa the giant crab from eating Maui, Moana covered a barnacle with a glowing substance and convinced Tamatoa that it was the Heart of Te Fiti, a gem that gives the holder the power to create life. Tamatoa fell for the trick and chased after the “Heart,” before realizing it was simply a fake coated in bioluminescent algae. This is great, because glowing algae is a real thing, and it’s pretty awesome.
Bioluminescence is ability for a living organism to produce and emit of light. The name comes from “bio,” the Greek root word for life, and “lumin,” derived from the Latin word “lumen” for light. Bioluminescence is a form of chemiluminescence, or the emission of light from a chemical reaction.
Basically, in these biological chemical reactions, a luciferin compound is oxidized (combined chemically with oxygen) by the enzyme luciferase, which is a protein that speeds up the chemical reaction. The reaction creates an excited intermediate state which decays to produce oxyluciferin and light. (Luciferin, luciferase, and oxyluciferin are all generic terms. The exact compound varies depending on the specific bioluminescent reaction.)
The color of light emitted depends on the type and arrangement of reaction molecules. Bioluminescent land animals typical give off yellow or green light, or sometimes red. Ocean bioluminescence is usually blue-green or green, which transmits best through seawater. (Red wavelengths are typically absorbed in the ocean and thus red light does not travel as far.) There are exceptions, of course, such as the deep-sea loosejaw fish, which produces red light search for prey that can’t see red light.
Many organisms exhibit bioluminescence for a variety of functions. Fireflies use bioluminescence to find members of their own species and choose mates. Some types of jellyfish give off bursts of light to startle predators. Anglerfish have appendages filled with bioluminescent bacteria that lure prey.
And like Moana illustrates, some types of algae show bioluminescence. Algae are aquatic organisms that can photosynthesize. Kelp, phytoplankton, and pond scum are just a few examples of algae. Dinoflagellates are single-celled algae that produce blue-green light when their water is disturbed by motion. The light is believed to both startle predators and attract secondary predators to feed on the primary predators that consume the algae.
When dinoflagellates are in large concentration, the result is visually stunning. If you’re lucky, you can see the light show in nature. Glowing algae have been seen the Gippsland Lakes of Australia, Mosquito Bay in Puerto Rico, the southern coast of California, Reethi Beach in Malidives, and even Norfolk, United Kingdom.
And I guess you can find it in Lalotai, the Realm of Monsters, but I’m not sure it’s the best place to visit.
Keep calm and science on.