You may have seen pictures of blue, glowing beaches under a dark sky. This glow is called bioluminescence. It is emitted by tiny organisms called bioluminescent algae that live in the water.
Bioluminescent algae are glowing algae that are found in oceans worldwide. They appear like flashes of bluish-green light when there’s any disturbance in the water they live in.
Here’s everything you need to know about bioluminescent algae and why they glow.
What Is Bioluminescence?
Bioluminescence is a type of chemiluminescence: that is, a chemical reaction that produces light. Bioluminescence occurs when a chemical reaction inside a living organism produces light as a byproduct. Doing so creates a glowing or twinkling effect.
It is a type of mechanism observed in marine animals like algae or squid. It helps some animals attract food for survival.
It is known as a "cold light" because it appears bluish and generates little heat. Bioluminescent marine organisms including fish, bacteria, jellyfish, and algae are found in the ocean waters. Bioluminescent organisms such as fireflies and certain fungi can be found on land.
The chemical reaction that causes bioluminescence involves the chemical luciferin. Some bioluminescent organisms produce these chemicals themselves, while some get it through their food.
Luciferin is a complex substance that produces light. Luciferase is an enzyme or a chemical that helps speed up a reaction. It allows oxygen molecules to bind to luciferin. This reaction is called oxidation. Once luciferin binds to oxygen, it produces oxyluciferin and emits energy in the form of light. The color and intensity of the light vary depending on how the luciferin molecules are arranged in an organism and depending on the type of luciferase enzyme.
Some organisms have chemicals called photoproteins, which combine with luciferin and oxygen. They don’t require luciferase to give out light as a byproduct. Instead, they produce light when they come in contact with calcium ions.
Bioluminescence must not be confused with fluorescence. Florescence occurs in the presence of a stimulating light, which is absorbed and then emitted over long durations.
What Is Bioluminescent Algae?
Bioluminescent algae are tiny, marine algae that produce a bluish-green light. They are single-celled organisms. Dinoflagellates are the most common type of bioluminescent algae that grow on the surface of the ocean. Noctiluca scintillans, also known as sea sparkle, is one such bioluminescent dinoflagellate.
Why Does Bioluminescent Algae Glow?
Bioluminescent algae produces luciferin and luciferase. Luciferase in dinoflagellates is similar to the green plant chemical called chlorophyll. The chemical reaction occurring between luciferin and luciferase is triggered when the bioluminescent algae are disturbed by movement or changes in the environment.
In dinoflagellates, the luciferase enzyme and luciferin molecule are present within a round structure called scintillon. A disturbance or change in the environment leads to stress on the covering or outer membrane of the dinoflagellate cell, which stimulates certain reactions within the cell. This causes changes in the scintillon, making it more acidic.
These changes activate the luciferase enzyme and speed up the binding of luciferin to oxygen. The chemical reaction produces oxyluciferin and generates light as a byproduct.
Bioluminescent algae glow for a short time when they are disturbed. However, changes in the environment, like a decrease in the saltiness of the water, can force bioluminescent algae to glow continuously.
In such cases, they look like sparkling blue or green spots in the dark ocean.
Is Bioluminescent Algae Harmful?
Bioluminescent algae appear mesmerizing on a backdrop of dark waters. Looking at bioluminescence can be the most beautiful experience. However, it may be a warning sign because many bioluminescent dinoflagellate species are toxic.
They can be poisonous to fish that swim around them. If you come in contact with such bioluminescent algae, they can be harmful to you too. Some species, like the sea sparkle, are not very poisonous but can still have unpleasant side effects.
Evidence also suggests that bioluminescence can be a sign of changes in the environment, including pollution and global warming. Environmental changes can cause low oxygen and high nitrogen and phosphorus levels in the water. Toxic dinoflagellates tend to reproduce and grow rapidly in such conditions, resulting in a harmful algal bloom. This can further lead to a phenomenon called “red tides.” Millions of overgrown toxic algae change the color of the water to red in daylight and cause it to sparkle at night.
During red tides, marine animals like fish or shrimp that eat algae also become poisonous as dinoflagellate toxins accumulate in their bodies. If you come in contact with the algae or eat these toxic sea creatures, you may have side effects like bowel problems or food poisoning. Some dinoflagellates produce neurotoxins, which can affect your brain function and memory.
Is It Safe to Swim in Bioluminescent Water?
Some bioluminescent algae produce toxins that are harmful to marine wildlife, humans, and anything that comes in contact with them, so it may not be safe to touch the algae or swim in bioluminescent water. You can visit sea shores that have bioluminescent algae, but it’s best to avoid contact with the algae and watch the glow from a safe distance.
Where Is Bioluminescent Algae Found?
Bioluminescent algae blooms during the summer months in the waters along the US mainland. It often gathers in warm-water lagoons or bays with narrow openings. This prevents algae from escaping into the open sea. At night, the whole lagoon appears sparkly and illuminated.
Bioluminescence can’t be seen in daylight. If you’re trying to spot it with your naked eye, it can be faint, especially if there are lights around. On a dark beach on a moonless night, though, you can see dinoflagellate bioluminescence in waves that break on the shore. As they get washed up on the shore, you may spot some as you walk along the beach. You may also see it in the wake of a boat or as a shape in the water.
Ongoing Research
Scientists are studying the use of bioluminescent algae in architecture. Because these algae can produce light, they have potential uses as a sustainable, eco-friendly light source. Using them can eliminate the need for electricity, which is powered by fossil fuels, and help protect the planet.
Apart from this, human-computer interaction designers are trying to study and understand how biological creatures can improve digital communication. Bioluminescent algae are like tiny, self-sufficient computers, and they allow scientists to study how they process information and interact with their surroundings. This can help create new and unique digital systems for human convenience.