Bioluminescence, the emission of light by living organisms, is a beautiful adaptation mechanism that many creatures on Earth have evolved to acquire. 

Bioluminescence occurs when two proteins, luciferin and luciferase, are combined in the presence of oxygen. In bioluminescent organisms, luciferase catalyzes the oxidation of luciferin, and this reaction produces light. The emission of light will continue until all of the luciferin has been oxidized. 

Some bioluminescent organisms produce their own luciferin. One example is dinoflagellates, which bioluminesce a bluish-green hue. Some bioluminescent organisms, however, are incapable of producing luciferin on their own, and instead acquire it by consuming, or forming symbiotic relationships with, other organisms. For instance, luciferin is obtained by midshipman fish from the seed shrimp they consume. Many marine animals, including squid, have a symbiotic relationship with bioluminescent bacteria in their light organs.

Bioluminescence serves several purposes. Anglerfish use their light organs, which dangle from their forehead, to lure in their prey. Some squid and shrimp produce a luminescent cloud to startle their predators and confuse them as they flee. For other living organisms in ocean depths where sunlight is scarce, bioluminescence is used to camouflage themselves. Their bioluminescence matches the color and brightness of the dim sunlight, making them more challenging for predators to detect. 

Bioluminescence can also be used for communication and mating. The best known example of this is the bioluminescence of fireflies. Males and female fireflies exchange flashes as a way of communicating to their possible mates. Females react to the flashes of flying males, and eventually, the male approaches the female for the purpose of mating. To avoid confusion between members of different firefly species, each species’ signals are coded in a distinct temporal sequence of flashing.

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References

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Ocean, S. (2023). Bioluminescence. Smithsonian Ocean. https://ocean.si.edu/ocean-life/fish/bioluminescence

Latz, M. (n.d.). A History of Marine Bioluminescence According to E.N. Harvey. Latz Laboratory. https://latzlab.ucsd.edu/bioluminescence/a-history-of-marine-bioluminescence-according-to-e-n-harvey/

The History of Luciferin and Luciferase  (n.d.). Gold Biotechnology.

https://goldbio.com/articles/article/The-History-of-Luciferin-and-Luciferase-discovery-timeline#:~:text=Initial%20Records%20of%20Bioluminescence%20(BCE%2D1500s%20AD),-Bioluminescence%20has%20struck&text=The%20first%20Greek%20reference%20to,were%20capable%20of%20self%2Dluminosity

Latz, M. (n.d.-b). Bioluminescence Questions and Answers. Latz Laboratory. https://latzlab.ucsd.edu/bioluminescence/bioluminescence-questions-and-answers/#:~:text=Probably%20bioluminescence%20originated%20in%20the,is%20detected%20by%20other%20organisms

Amber-encased fossil shines light on evolution of bioluminescent insects: Preserved with “life-like” fidelity, beetle from the Cretaceous is fireflies’ missing fossil link. (2021, January 21). ScienceDaily. https://www.sciencedaily.com/releases/2021/01/210119194401.htm

Bioluminescence. (n.d.). National Geographic https://education.nationalgeographic.org/resource/bioluminescence/

En, H. (1927). THE OXIDATION-REDUCTION POTENTIAL OF THE LUCIFERIN-OXYLUCIFERIN SYSTEM. The Journal of General Physiology, 10(3), 385–393. https://doi.org/10.1085/jgp.10.3.385

The Explorer’s Guide to Biology. (2021, October 20). Bioluminescence and Luciferase [Video]. YouTube. https://www.youtube.com/watch?v=cws1zUbhaSI

University of Rochester Biochemistry (Biol252). (2018, May 15). Luciferase [Video]. YouTube. https://www.youtube.com/watch?v=odN92KbH8Bo

Real Science. (2022, November 26). Why Is (Almost) All Bioluminescence in the Ocean? [Video]. YouTube. https://www.youtube.com/watch?v=jJdLiKYKWzY

Bgr. (2020, May 7). Red tide lights up California’s coast with bioluminescent plankton. New York Post. https://nypost.com/2020/05/07/red-tide-lights-up-californias-coast-with-bioluminescent-plankton/

TED-Ed. (2013, March 29). The weird, wonderful world of bioluminescence – Edith Widder [Video]. YouTube. https://www.youtube.com/watch?v=lKeDBpkrDUA