Mad About Science: Bioluminescence

By Brenden Bobby
Reader Columnist

In the age of smartphones and mass-produced LEDs, light isn’t really a big deal to us anymore. Our vehicles spout light in every direction at night. We have powerful flashlights to illuminate our way in the creepiest of crawl spaces. Our planet is so well-lit, it’s actually getting harder to see the stars at night, no matter where you are.

Because of this, I will forgive you if you don’t take much stock in the contents of this article.

Then again…

To tell the guy behind you that you’re turning, to light up the creepy crawl space under your house, to blot out the night sky with light, you need a device that’s the culmination of more than 140 years of engineering.

The things in this article make light on their own.

Like a BOSS.

So you’ll have to forgive me if I don’t take much stock in you not taking much stock in the contents of this article!

Bioluminescence is a chemical reaction in which a biological function creates light. Not with the flick of a switch, press of a button or a mechanical device, but with its own body.

The most universal example I can think of is the firefly. Everyone knows about fireflies, lightning bugs or, for your inner entomologist, lampyridae. They’re flying beetles with glowing butts.

Fireflies glow for all sorts of reasons. Larvae glow to warn predators that they taste funky, and shouldn’t be eaten. Adults glow to attract prey and mates.

One thing I didn’t know until I started researching this subject is that the light emitted from fireflies doesn’t have an infrared or UV frequency.

That means that Apache attack helicopters and AC-130 gunships are not amongst the firefly’s natural predators.

Fireflies aren’t the only creatures with a knack for bioluminescence. We’ll get to the others later, but first we’ll learn about what makes them glow.

Bioluminescence is achieved similarly across most species capable of producing light. In virtually all cases, luciferin and/or luciferase are involved. If that sounds ominously familiar, it’s because it’s named after Lucifer, the light bringer.

No worries, glow bugs aren’t part of a satanic cult or anything.

In most cases, the luciferase is an enzyme that interacts with magnesium and oxygen to catalyze a reaction that creates light. In some cases, it’s much more complex than this, but in most cases it’s pretty simple.

We’ve actually injected luciferase into other creatures, and ourselves, for curious purposes of artistic and scientific endeavor.

What sort of creatures have we made glow, you might ask?

Sheep, dogs, cats, a rabbit and several types of fish to name a few. We even inject ourselves with bioluminescent dyes to track tumors and certain cells, or chemical pollutants in our bodies. Bioluminescent enzymes are also useful for forensics in a range of applications from bodily fluid detection to testing for doping in sports.

Want a bioluminescent pet of your own? It’s as easy as a trip to the pet store. Humans have inserted bioluminescent jellyfish genes (as well as the genes of sea anemones, coral and sea pansies) into the embryos of zebra danios to create brilliantly colored fish that seemingly glow in the dark (when interacting with certain wavelengths of light or other chemicals). They come in all colors of the rainbow and are pretty inexpensive, and as far as we can tell, this form of genetic engineering doesn’t do any harm to them in an aquarium.

Their ability to glow in the presence of certain chemicals also gives them the unique ability to inexpensively detect chemicals we can’t normally see in water.

Despite heavy resistance to gene-altering sciences in areas such as food (corn, grain, other GMOs), and human embryos, the public has widely accepted the gene altering and patenting of glowing fish.

Me, I still think it’s weird that you can patent, trademark and brand a living creature, but that’s an existential conundrum for another day.

Some creatures are too small to see, even when they’re glowing. Once they gather in the millions, billions, or even more, they’re clear as day. Dinoflagellates are a form of plankton, and some of them can glow a distinctive blue. It’s pretty cool seeing the crests of waves glow a haunting sapphire blue.

Dinoflagellates are also responsible for the dreaded red tide, a form of algal bloom that turns water a reddish-pink and poisons anything that swims in it.

You know what they say: strength in numbers.

Not to be outdone by the macro and the micro, fungi are famous for their ability to glow in the dark. Foxfire is one of the oldest known examples, having been cited by Aristotle, experimented on by Pliny the Elder, tinkered with by Benjamin Franklin and written about by Mark Twain.

Foxfire is a bit of a conundrum, its name being somewhat of a mistranslation from the french “faux” meaning false. While foxes and kitsune might have gotten a cool reputation as fiery mischief-makers thanks to this freaky fungus, maybe we should’ve been calling it foe-fire all this time.

This is just the tip of the glowing iceberg. There are over 200 aquatic species capable of bioluminescence that we know about, and that’s not even counting coral, algae, fungi, or those awesome glowing sheep we developed.

Curious about owning some glowing creatures of your own? Before you nuke out your room, maybe inquire at the pet store and see what it’d take to get some sweet glowing coral. Who needs a night light when you have crazy biology?