Why do so many deep-sea creatures produce their own light?
In the ocean's midnight zone, making your own light isn't a luxury - it's the difference between eating and being eaten.
The answer
Bioluminescence occurs in over 76% of deep-sea organisms, making it the most common form of communication in the ocean. Creatures produce light through chemical reactions between luciferin and luciferase enzymes, or via symbiotic bacteria housed in specialized organs called photophores. The anglerfish dangles a glowing lure to attract prey. Vampire squid eject bioluminescent mucus to confuse predators. Hatchetfish use counter-illumination, matching their belly glow to faint surface light to erase their silhouette from below. A 2021 study in PLOS ONE cataloged bioluminescence in over 1,500 fish species, confirming it evolved independently at least 27 times across fish lineages alone.
Source: Smithsonian Ocean
- bioluminescence
- deep sea
- marine biology
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