What is bioluminescence? It’s a living light

What is bioluminescence?

When you hear the word bioluminescence, do you think of glowing ocean waves under a dark sky? Many do. But, bioluminescence includes all life that – through a chemical reaction – emits light. In the image above, a single-celled form of marine plankton, known as bioluminescent dinoflagellates, are the source of the light on the incoming waves. But in addition, there are bioluminescent creatures in the deeper ocean, too. And we here on Earth’s dry land sometimes see bioluminescent creatures flying in the air.

First, about the image above, which is from the Maldives, an island nation in the Indian Ocean, southwest of Sri Lanka and India. According to the Visit Maldives website:

These dinoflagellates use a chemical called luciferin to emit a bright blue light as a defense mechanism … The flashes of light produced by the dinoflagellates can disorient and confuse predators.

The movement of the waves can also trigger this light emission, resulting in the mesmerizing sight of glowing waves washing ashore in the Maldives.

Bioluminescence: Blue glowing waves lapping up on a beach in the dark with stars overhead.
View at EarthSky Community Photos. | Petr Horálek captured this bioluminescence on February 14, 2023, and wrote: “What a wonderful night at Soneva Jani Island in the Maldives. After stargazing at the So Starstruck observatory, I visited the northern beach and couldn’t believe my eyes. The whole beach shone with turquoise light, the gems of the Southern Cross constellation above. Locals say the bioluminescence of plankton peaks in early January. But this year the activity lasted a month more. This night was simply epic. You could walk on the beach with the plankton stuck on your feet like torches. You could swim in the lagoon, and your movements were illuminated in the water. It felt like a turquoise wonderland.” Thank you, Petr!

How do living creatures make light?

Luciferin is the key to these creatures that emit living light. Luciferin is a molecule that reacts in the presence of the enzyme luciferase to produce light. Indeed, the words come from lucifer, which is simply Latin for light-bearer.

The chemical reaction between the two splits off a molecular fragment. That, in turn, produces an excited state that emits light.

In the video below, you can see how scientists are studying undersea creatures to learn more about bioluminescence.

Other sources of bioluminescence

Bioluminescence is common in marine life, such as jellyfish, sharks, crustaceans and fish. However, it can occur on land too, in worms, fireflies and even plant life such as mushrooms. In fact, here’s a list of 10 mushrooms that glow in the dark.

Irregular curved green lines and concentric star trails above backyard grass and trees.
View at EarthSky Community Photos. | Dan Bush in Albany, Missouri, captured fireflies and star trails on June 18, 2022. He wrote “The circular arcs in the sky are circumpolar star trails. The horizontal white streaks in the middle of the image are the headlights from cars passing by. And the curved green/yellow streaks mostly against the moonlit landscape are from lightning bugs, or fireflies, depending upon which part of the world you live.” Thank you, Dan!

Where to see bioluminescent life

As shown above, you might be surprised to learn that bioluminescent life is all around us on planet Earth. Indeed, from glowworms inside caves in New Zealand to fluorescent fungi in Japan to fireflies in your backyard, you don’t have to travel too far to see examples of it.

If you’re interested in bioluminescent beaches, try Mosquito Bay in Puerto Rico or the Luminous Lagoon in Jamaica.

Meanwhile, parts of Tennessee, North Carolina and South Carolina offer not just fireflies, but synchronous fireflies, where groups of the glowing creatures all turn their lights on and off in tandem, while searching for mates.

Learn more with this list of more than 20 places to see bioluminescence around the world.

Boat floating on dark water with blue dots near the shore and a starry background.
View at EarthSky Community Photos. | Petr Horálek captured this image on February 24, 2023. Petr wrote: “The boat in the center of the image is named ‘Amazing View’ as it belongs to Moosa Farooq of the Amazing View Guest House of Thoddoo, Maldives. And yes, there are amazing views around the island, not only in the daytime. The boat – calmly anchored close to the beach – is surrounded by both marine and sky universes. On the water’s surface, the numerous ‘sparkles’ belong to the bioluminescent plankton. Far away, over the Indian Ocean, the majestic Orion constellation sets, followed by the Milky Way, bright star Sirius, and hydrogen nebulae not visible to the eyes. What an amazing view!” Thank you, Petr!

Share your images!

Do you have a photo of bioluminescence? Share it with us!

Water with light on the incoming waves plus the Milky Way and other lights behind.
View at EarthSky Community Photos. | Amr Abdulwahab in Fayoum Oasis, Egypt, captured this image on August 13, 2023. Amr wrote: “On August 13, I was shooting a timelapse of the Perseids meteor shower from the shore of Lake Rayan in Fayoum Oasis in the Western Desert of Egypt, when I saw lights twinkling on the shore of the lake. At that time, I did not know what these lights were, but when I asked one of the fishermen in the lake, he told me that they were jellyfish. And as soon as I returned to the city and shared the pictures, my colleagues told me that it was the phenomenon of bioluminescence of a type of bacteria.” Thank you, Amr!

Bottom line: Bioluminescence is living light. From plankton to jellyfish to fireflies, many creatures around the world can glow in the dark.

March 17, 2023

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