Bioluminescent Algae: Glowing Environmental Warriors

Table of Contents

Only ten percent of the ocean has been explored. It is full of mystery and surprises, with beauty at every depth. One mysterious sight in the ocean is bioluminescent algae. Bioluminescence  is when an organism glows or shines a bright light. Fireflies are a great example of a bioluminescent organism. Even though they are very different from algae, they shine in a similar way, lighting up the sky as they glow. Algae are organisms that can live in the water and make their own food through photosynthesis like plants do. They can be made of one single cell or have many cells. These tiny organisms have many important jobs and are important to the global food chain.

A time-laps photo of fireflies showing bioluminescence
A time-laps photo of fireflies showing bioluminescence. Credit: Flickr/Mike Lewinski

How do bioluminescent algae glow?

Chemical reactions include reactants and products . Reactants are chemicals that work together to make products, which are the result of a reaction. Bioluminescence is caused by a chemical reaction involving luciferin and luciferase . Luciferase is an enzyme, which means it causes a chemical reaction to happen more easily. Imagine you are blindfolded and asked to walk across a room and turn on a light. This might be easier to do if someone came to hold your hand and walk you in the right direction. The person holding your hand is like an enzyme. The enzyme helps to speed up a chemical reaction. Just like a person holding your hand while you are blindfolded, luciferase helps the luciferin reactant to work with other chemicals and make light as a product. But why do algae need this glowing chemical reaction?

Why do algae glow?

Glowing algae is a signal that something is wrong in the water. This chemical reaction that causes a blue-green glimmer happens when algae is disturbed. Algae is very low on the food chain. When predators attempt to consume algae, bioluminescence comes to the rescue. Groups of algae can come together and form blooms , making a bright blue light in the water at night. Bioluminescence has two main jobs during this time. First, it alerts larger predators to come eat the smaller predators that are disturbing the algae. Next, the algae is toxic  to eat. This means that if predators eat enough of the algae, they can get very sick. The bright light is a signal to these predators not to eat the algae for their own safety.

An algal bloom in the Baltic Sea. Credits: Flickr/Steve Jurvetson

Why do we need algae?

It is a good thing that algae can protect themselves through bioluminescence, because algae is extremely important to the environment. It is a food source for many predators, but it also has a very important job. Algae remove carbon dioxide from the atmosphere through photosynthesis, just like plants do. However, algae remove 10–50 times more carbon dioxide than plants. They are environmental warriors, and it’s important that they remain protected and healthy. As climate change continues to become a threat and carbon dioxide levels rise in the environment, it is actually easier to spread algae than it is to grow plants. For this reason, algae are becoming a key tool to fight climate change and clean up the air that we breathe.

Where is bioluminescent algae found?

We know that algae can glow when they are threatened, but algae can also glow if the water saltiness changes or if the climate changes. In some regions of the world, bioluminescent algae glows the most in the summer. In some regions, it can glow all year long. Some of the best places to see bioluminescent algae are in enclosed bodies of water like bays, where algae cannot easily escape into the ocean.


These glowing organisms can be seen all around the world. The Matsu Islands in Taiwan, Mosquito Bay in Puerto Rico, Jervis Bay in Australia, Luminous Lagoon in Jamaica, and San Diego in California are all places where you can see bioluminescent algae.

Someone surfs on a bioluminescent wave in San Diego. Credits: Wikimedia/Timothy R Fallon

Is it safe to swim with bioluminescent algae?

Even though it might be tempting to go into those glowing waters, scientists say it is not the safest idea. Remember that algae are toxic to their predators. That blue-green glow is a defense mechanism to keep predators away, and humans should also steer clear. If you really cannot resist getting closer, some glowing algae bays have kayaking tours to go out on the water and watch the algae shine around you. If the algae are not around to show off their glow, other organisms may be able to put on a show, too.

Do other organisms glow?

Tiny algae are not the only organisms that glow. In fact, up to 76% of ocean organisms have bioluminescence, including jellyfish and sea stars. Organisms of all shapes and sizes glow for different reasons. Like algae, they can use it as a defense mechanism. But some organisms use their glow-y powers to help find mates! Bright lights serve many purposes in the mysterious ocean.

Bioluminescent jellyfish. Credits: Flickr/Jason Eppink

How is bioluminescence used in scientific laboratories?

One more unexpected use for bioluminescence happens in scientific laboratories. Scientists can create cells that make luciferase and produce bioluminescent light during specific conditions. These cells are used by scientists who study all different kinds of diseases, from cancer to viral infections. Who knew that a bioluminescent glow could be such a useful tool to scientific discovery?


Bioluminescence: when an organism makes a glowing light


Algae: organisms that live in the water and use photosynthesis to make food. Can be single- or multicellular.


Reactants: Chemicals that work together to make a product in a chemical reaction


Product: The result of a chemical reaction


Luciferin and Luciferase: Key pieces of a chemical reaction that makes bioluminescence


Blooms: groups of algae


Toxic: poisonous when too much is eaten or ingested

Flesch Kincaid Score: 57.8

Flesch Kincaid Reading Level:
10-12th grade


  • Tess Bub
    : Author
    Tess Taggart Bub has a bachelor’s degree in biochemistry and a minor in data science from Houghton College. During her undergraduate studies, she conducted research in the areas of climate science, ecology, and muscle biology. She is currently a PhD candidate at the University of Tennessee Health Science Center studying host cellular response to viral infection. She is a strong believer that science can change the world, especially when it’s shared. In her free time, she loves communicating science, playing guitar and piano, and running. Writing for smore gives Tess the opportunity to help inspire a new generation of women in STEM.

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