Author: Cindy Hu
From: West Orange, NJ, USA
Bioluminescence on a beach
Any fan of the Harry Potter saga is familiar with the spell for light. Besides being a fun word, “lumos” also appears to have its roots in Latin: “lumen” means “light,” and the suffix “os” means “to have.” When you combine the two, “lumos” means “to have light!”
Magical incantations aren’t the only words that can be derived from Latin; in fact, much of the English language has been influenced by the classical language. Along with “lumos”, we have words like “illuminator,” “luminous,” and “luminary,” - all rooted in the Latin term for “light.” We also have this complex term: “bioluminescence.”
What is bioluminescence?
Besides being one of the longest words I’ve ever seen (and one of the hardest to spell), bioluminescence is exactly what it sounds like: “bio-” meaning “life” and “luminescence” meaning “light”. Living light.
Bioluminescence can be observed in a variety of creatures, from fireflies to algae and even sharks. In fact, up to 90% of marine creatures have this ability!
Organisms emit light for numerous reasons. For some, such as the firefly, bioluminescence offers a form of communication. Different species of fireflies emit different patterns of light, so bioluminescence helps fireflies identify one another. It also helps them find mates: studies have shown that female fireflies prefer males with specific flash characteristics, including increased intensity.
For other creatures, bioluminescence is a great form of lazy hunting. Prey are often attracted to light, so some animals use that to their advantage by luring prey towards them with bioluminescence. Examples include deep-sea anglerfish and cookie-cutter sharks. Cookie-cutter sharks are especially notorious for latching themselves onto bigger predators (including great white sharks!) once they get too close and taking a bite. Stay away from strange light sources!
How does bioluminescence work?
Bioluminescence is a chemical reaction that requires a compound called luciferin. Luciferin is not a specific substance; rather, it is a term encompassing many substances that fit this reaction. Some reactions also involve luciferase, an enzyme that helps the reaction happen faster. Other reactions not containing luciferase can contain a photoprotein. This is a chemical that reacts with the luciferin and oxygen but often needs a calcium ion to produce the desired light. An ion is any molecule that has gained or lost electrons and thus has a net electric charge.
Depending on the species, the produced light can vary in terms of color and duration. Marine animals often exhibit blue-green light because it is more visible in the ocean water, whereas fireflies glow yellow and railroad worms can be both red and green. Fungi can emit light for long periods of time, something known as foxfire. On the flip side, fireflies and certain species of squid usually only emit light in quick flashes.
As the search for environmentally-friendly fuels continues, some have turned to bioluminescence as a source of gentle, natural lighting. Designer Teresa Van Dongen, the creator of the Ambio, was one example: as a graduation project for the Eindhoven’s Design Academy, she used bioluminescent photobacteria as the source of light for her lamp.
The bacteria inside the lamp glow blue as long as there is enough oxygen and movement. To ensure that there would be enough motion for the bacteria to glow, Van Dongen attached weights to the lamp so that it would move for up to 20 minutes whenever it was pushed. While the lamp isn’t practical for reading, it still offers a form of natural lighting. Plus, it looks like a night light and a glow stick put together!
Similarly, researchers at MIT have created bioluminescent plants by injecting the reactants needed for bioluminescence into plants. They did this with a watercress plant, which glowed for about 4 hours afterward. While neither this plant nor the Ambio lamp are technologically advanced enough to replace regular lightbulbs, they are still incredibly interesting. With more research, someday we might be able to use them as eco-friendly light sources!
Bioluminescence and pollution
Unfortunately, this incredible chemical reaction does have a downside. In the past, scientists in places like Florida have spotted unusual amounts of bioluminescent plankton in the water. This is not a good sign: algae blooms are harmful to dolphins, sea turtles, and fish, and also contaminate drinking water. The toxins produced from algae blooms can even taint shellfish beds. While the scene is spectacular - the entire river glows in the dark - the consequences aren’t.
Algae blooms are typically a sign that something is wrong with the ecosystem. Sometimes they are caused by nitrogen pollution: livestock waste and many kinds of fertilizers contain nitrogen, and the runoff will go into lakes and rivers. Other times, algae blooms are caused by the water growing warmer than usual. Either way, glowing water is a warning.
Bioluminescence is a magnificent chemical reaction that has lots of potential for more research. Animals all over the world have harnessed its powers, and humans are just starting to uncover its secrets. It is not impossible for us to have bioluminescent lamps and streetlights in the future. Likewise, because bioluminescent algae blooms are sometimes a warning signal, bioluminescence can also be used to monitor the presence of harmful substances (such as too much nitrogen) in bodies of water.
Now, we just have to fill a wand with the right combination of bioluminescent bacteria and give it a wave. The wand motions will disturb the bacteria, which will light up. Perhaps one day we’ll have our own lumos spell. Who said Muggles couldn’t do magic?
Author: Cindy Hu
Cindy is a high school junior in NJ who loves math, physics, and biology, among many other subjects. Her hobbies include reading, playing the piano, and learning to crochet.
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