Let it glow, let it glow, let it glow

The New Year’s Eve fireworks may be behind us but, believe it or not, fabulous fireworks displays play out in dark ocean waters around the world every day. According to NOAA Senior Scientist and Deep Sea Researcher Dr. Edie Widder, “Bioluminescence in the ocean is the rule rather than the exception.”

biouminescence in the animal kingdom

First things first: what’s bioluminescence? It’s the production of light from a chemical reaction inside an organism, produced by animals for defense, attracting mates or finding food. Numerous deep sea creatures exhibit bioluminescence and more than a few light-producing organisms are found right here in Puget Sound—some of which are even housed at Seattle Aquarium.

Bioluminescence is sometimes confused with other forms of light:

  • Fluorescence—When particular wavelengths excite a material, i.e. black light or the green fluorescent protein (GFP) in the Aequorea Victoria jellyfish.
  • Phosphorescence—Similar to fluorescence, where a material is excited but has a longer-lasting effect, i.e. glow-in-the-dark stickers or many species of coral.
  • Iridescence—When light is separated into component wavelengths and we see distinct colors in close sheens, i.e. soap bubbles, beetles, abalone shells.

Evolution of fish bioluminescence

According to a study conducted in 2016, fish evolved to make their own light at least 27 separate times. Bioluminescence is likely a much more common phenomenon than most people would think. It is found in over 700 genera of organisms; eighty percent of these occur in the ocean.

This study looked just at ray-finned fishes and not at other types of bioluminescent organisms. In these fishes, bioluminescence can be intrinsically generated (produced by a chemical process within the fish’s own body) or generated through bacterial symbiosis (bioluminescent bacteria are housed within the fish’s body).

Intrinsic bioluminescence evolved eight separate times throughout history, with more than half of known bioluminescent fish species utilizing this method of producing light. Of the 1510 known bioluminescent ray-finned fishes, about 785 produce their own light, though it is unknown how most of them obtain the necessary components for the chemical reaction (in at least some species it appears to be through their diet). Bacterially aided bioluminescence evolved at least 17 separate times.

Bioluminescence in human history

Bioluminescence holds a special fascination for many people. Imagine being able to produce your own light—it sounds like some kind of superpower! And yet it’s remarkably common among many animals, especially in the deep ocean. Although humans are not capable of bioluminescence, we have found opportunities throughout history to appreciate and utilize this ability in other creatures.

For example, Aristotle wrote about bioluminescence in his work De Anima in 350 B.C. During World War Two, Japanese soldiers used dried ostracods, a type of bioluminescent plankton, as a source of light. In 1954, James Lovell followed a bioluminescent wake to land his fighter plane on an aircraft carrier after his instruments failed during a night flight. And today, we have toys that allow anyone to capture the wonder of bioluminescence.

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