Delve into the captivating glow of bioluminescence and fluorescence—how they fit into Anne’s stories and their fascinating real-world inspirations.

Hello, this is Anne Renwick, steampunk romance author, bringing you into the laboratory today to delve into the captivating world of bioluminescence—and to a lesser degree, fluorescence—how these natural wonders inspire my stories, and their fascinating real-world roots.

Bioluminescent Ocean Waters and The Decilamp

If you’ve read The Golden Spider, you might recall the opening scene where two agents are tracking down a suspect, and at one point they pull out something I’ve called a decilamp. What’s a decilamp? If you’ve done any science, you’re familiar with the metric system: meters and liters, deciliters and decimeters—units representing one-tenth of a meter or liter. So, I named this handheld sort of flashlight—or if you’re British, a torch—a decilamp.

Throughout The Golden Spider, my characters often use this bioluminescent light, shaking it first before it glows blue, white, or blue-green. This glow comes from activating the bioluminescent bacteria inside the device, which emit a beautiful biological light.

Later, in The Iron Fin, I introduce another illumination device called the Lucifer lamp. The name Lucifer comes from the term “light-bringer,” tying directly to the biological enzymes luciferin and luciferase, which produce light in bioluminescent organisms. These enzymes were discovered in the late 1800s by a French scientist named Raphaël Dubois.

A Childhood Memory: Puerto Rico’s Bioluminescent Bays

Why am I so fascinated by bioluminescence? Let me share a story.

When I was about nine, my family took a trip to Puerto Rico, which is famous for its three bioluminescent bays. Unlike the bacteria in many waters, these bays glow thanks to tiny plankton called dinoflagellates. When disturbed—say, by a boat’s wake or a splash—these plankton emit bursts of blue-green light.

The brightest bay, Mosquito Bay, located off a smaller island near Puerto Rico, is considered the brightest bioluminescent bay in the world. It’s a protected natural wonder that was temporarily dimmed after Hurricane Maria in 2017 but has since bounced back stronger than ever.

I visited a different bay on Puerto Rico’s southern shore, known simply as Bioluminescent Bay. Although it’s not as vibrant as it once was—affected by light pollution, runoff, and ecological changes—it remains a magical place. I remember gliding through the water in a small rowboat, dipping my hands into the water, and seeing sparks of blue-green light flash in response.

These light bursts occur at about 470 nanometers in wavelength, and they’re mesmerizing to witness. If you ever get the chance to visit one of these bays, don’t miss out!

Why Blue?

Blue-green light travels the farthest underwater. Red light, by contrast, is quickly absorbed and disappears in deeper waters. This is why the bioluminescent glow you see in the ocean is almost always in the blue-green spectrum.

For those in the U.S., bioluminescence might be closer than you think. During certain red tides—when algae blooms bloom and sometimes produce toxins—there are times when the water glows at night due to bioluminescent dinoflagellates. If you’ve witnessed a bioluminescent red tide, I’d love to hear your story!

Fluorescence vs. Bioluminescence

It’s important to distinguish fluorescence from bioluminescence.

• Fluorescence happens when an organism produces a fluorescent protein that absorbs light at one wavelength and emits it at another, longer wavelength. The organism doesn’t produce the light itself—it reacts to outside light.

• Bioluminescence is light produced by a chemical reaction within the organism.

For example, the Green Fluorescent Protein (GFP) has been a crucial tool in biology. I used GFP in my own research to track proteins inside cells. Scientists can extract the DNA coding for GFP and insert it into other proteins or organisms, creating glowing green cells or even animals. This kind of genetic engineering has expanded our understanding of biological processes in amazing ways.

The Chemistry of Bioluminescence

Bioluminescence results from a chemical reaction between two proteins: luciferin and luciferase. In the presence of oxygen, luciferase catalyzes the oxidation of luciferin, producing light as the molecule oxyluciferin forms and decays. This reaction only goes one way, so the organism must continually produce luciferin to keep glowing.

Some species also require cofactors like calcium, magnesium ions, or ATP (cellular energy) to power this reaction.

Why Do Organisms Glow?

Bioluminescence serves many purposes in nature:

• Counter-illumination: Helping organisms blend in by matching the light from above. For example, many sharks and dolphins have lighter bellies to blend in with the lighter sky when viewed from below.

• Mimicry and camouflage: To look like something else or confuse predators.

• Luring prey: Like the angler fish with its glowing lure to attract dinner.

• Repelling predators: To scare or confuse attackers.

• Communication: Fireflies flashing signals to attract mates.

• Creating light: Some deep-sea creatures use bioluminescence to see in the dark ocean depths.

The black dragonfish, for example, produces a rare red bioluminescent glow—which other animals can’t see. This gives the dragonfish a stealth advantage to spot prey without being noticed.

Classes of Bioluminescence

Scientists classify bioluminescence into six main groups:

Bacteria: Bioluminescent bacteria found in marine environments.

Dinoflagellates: Plankton responsible for glowing bays and some red tides.

Fungi: Wood-decaying mushrooms that emit green light, sometimes called foxfire.

Vargulin: Found in seed shrimp and the fish that eat them.

Coelenterazine group: Includes jellyfish, mollusks, squid, shrimp, worms, and some fish.

Firefly luciferin: Lightning bugs and fireflies producing flashes, requiring ATP.

Interestingly, no multicellular plants or most land animals naturally produce bioluminescence.

Bioluminescence Meets Genetic Engineering

While no natural multicellular plants glow, scientists have engineered glowing plants by inserting firefly luciferase genes into tobacco plants. This was my first encounter with luciferase in college, sparking my fascination with bioluminescence.

It’s conceivable that with advancing DNA technology, we could create glowing amphibians, reptiles, birds, or even mammals in the future.

Bioluminescence in The Iron Fin

In The Iron Fin, the character Isa McQuiston carries a Lucifer lamp—a biological light source grown from bioluminescent bacteria she tends like a living organism.

“First things first, she would begin by tending the lights and dispelling the gloom… She transferred a measure of bacteria from her boat’s light into the hall lamp, adding a sprinkle of powdered agar and other nutrients. Hoisting it aloft, she wound the rocking mechanism and stood back. The gel oozed from one end of the long cylinder to the other, slowly mixing bacteria with food and oxygen, rewarding her with a few tiny faint blue sparks.”

This fictional lamp is inspired by real-world efforts to harness bioluminescence as sustainable light.

Glowee: Lighting the Future with Bioluminescence

While researching, I discovered Glowee, a French company working to grow bioluminescent plankton in labs for lighting. Their goal is to produce sustainable, soothing light that’s easier on human eyes compared to harsh LEDs or incandescent bulbs.

Glowee is improving organism longevity, light intensity, and environmental tolerance to make bioluminescent lighting practical. If you’re in Paris, you might get a chance to visit their glow rooms and see their fascinating work firsthand.

Why Bioluminescence Matters to Me

As a steampunk author deeply interested in the industrial revolution’s legacy—particularly coal burning and its environmental impacts—I love incorporating biological light into my stories as a small nod toward a more sustainable future.

Thank you for joining me on this luminous journey through bioluminescence and fluorescence. If you have personal experiences with glowing bays, red tides, or bioluminescent organisms, please email me and share your stories.