American Oceans

Quick Facts: Bioluminescence & What Causes It

We’ve all seen those images of the glowing plankton on the beach. This magical and majestic sight looks like something out of James Cameron’s Avatar movie!

Those sparkling lights just twinkling on the shore of the water is truly something to behold, but what is this, and what causes this to happen?

Glowing lights in the ocean’s waters and shores is what is called bioluminescence. This is a biochemical emission of light caused by living organisms, which creates a glowing and twinkling effect in the water.

Is it safe to swim in bioluminescent water

With this guide, you can find out exactly what bioluminescence is, what causes it and what time of the year it occurs, so that maybe you can see this beautiful phenomenon for yourself, and understand it a bit more! So, what exactly is bioluminescence? 

What is Bioluminescence

In the most basic sense, bioluminescence is the light emitted by a living organism through a chemical reaction happening in their bodies.

Bioluminescence is therefore a certain type of chemiluminescence, which is the term used for a chemical reaction where light is produced, but we use bioluminescence because this reaction is taking place inside a living organism.

In addition to this, bioluminescence is considered cold light, which means that less than 20% of the light generates thermal radiation or any type of heat. This is also why it appears blue or whitish in color. 

This phenomenon often happens in water and in the oceans, and you will be able to see bioluminescent waters on the coast of Puerto Mosquito, Vieques in Puerto Rico.

bioluminescence photographed on a beach

This small bay on the tiny Caribbean island of Vieques has a glittering reputation for bioluminescent reactions.

Bioluminescence often happens in the ocean and in the water as this is where the most bioluminescent organisms are found.

Most bioluminescent marine creatures include jellyfish, bacteria, plankton, and fish. However, you can find bioluminescent organisms on land such as fireflies and fungi. 

How bioluminescent light appears can vary greatly depending on the particular organism and the habitat in which it is found.

However, for the most part, the majority of marine bioluminescence is experienced in blue and greenish parts of the visible light spectrum and will appear more visible in deep parts of the ocean, or at night when there is little light.

Is it Safe to Swim in Bioluminescent Water?

In some cases, bioluminescence is not harmful, as it is simply a natural defence mechanism of marine creatures like phytoplankton, shrimp and squid.

In other cases, the bioluminescent creatures can produce toxins that are harmful to fish, humans, and other creatures that come into contact with it, so it is probably best if you avoid swimming in bioluminescent waters just to be safe. 

Things like bioluminescent algae that twinkle along the seascape can poison sea life from fish to sea turtles and can make humans very sick if they come into contact with it, so swimming is not advised.

At the most famous bioluminescence location in the world, the Mosquito Bay in Puerto Rico, swimming with the organisms is no longer permitted.

Although the organisms glow when disturbed, it is best to leave nature to its own devices, in case of any damage caused, and to protect the marine life. 

Although this phenomenon is unbelievably amazing and a sight to behold, it is best to view from a distance, away from the organisms in case they are toxic, or disturbed in any way. 

Is Human Skin bioluminescent? 

Surprisingly, yes, human skin is considered bioluminescent. According to a recent study by Japanese scientists and researchers, human bioluminescence is possible and exists in visible light. However, our eyes are unable to pick up on this. 

The study concluded that the human body actually glimmers like other bioluminescent organisms, but the intensity of the light emitted by human bodies is about 1,000 times lower than what we can see with our naked eyes. 

In this study, the team used hyper-sensitive cameras to monitor volunteers for 20 minutes every 3 hours in a light-tight room for days.

The evidence showed that the human participants glowed during the day, with the brightest parts being the forehead, cheeks, and neck, with the dimmest amount of bioluminescence appearing at night. 

The images showed that photons of visible light appeared, illuminating the body and creating a glimmer.  However, this does not work in the same way as other bioluminescent organisms, it is more of our own form of glowing bioluminescence.  

Is Bioluminescence a Bad Sign?

Whilst witnessing or experiencing bioluminescence can be a beautiful thing, it may actually be a bad sign. For example, bioluminescent dinoflagellates can be a sign of danger, as many species in this group are considered toxic.

They can be harmful to the fish around them and even poisonous to humans if they come into contact with us. Other species, such as the sea sparkle, are not as toxic, but can still have unpleasant effects on wildlife. 

Other studies have shown that bioluminescence can be a sign of an unhealthy ocean, and a result of global warming.

Researchers have found that global warming may be fueling the rapid growth and increase of bioluminescent marine plankton that is incredibly harmful to the fish in its environment. 

Is bioluminescence a bad sign

This is largely because these microscopic organisms such as plankton often bloom in areas where there are low levels of oxygen and higher levels of nitrogen and phosphorus. Whilst this causes plankton to bloom, it is typically bad news for marine life and the food chain.

In addition, the algae that bloom in these areas exposes the pollution in the water and is typically followed by the deaths of masses of fish due to the toxins, and low oxygen levels where this happens. 

That being said, whilst in some areas, bioluminescence can be a result of climate change, in other places it occurs naturally due to the wildlife and organisms in the region. 

Is Bioluminescence Hot or Cold?

As mentioned above, bioluminescence is considered to be cold light. The chemical reaction that causes bioluminescence produces so little amounts of heat, that it is considered a cold light, and a cold glow.

This is also why bioluminescence is blue, whitish, or green in appearance, as these are cooler colors on the visible light spectrum. 

What Time of Year Does Bioluminescence Occur? 

Generally speaking, the summer months are the best time of the year to find and watch this glowing phenomenon. This is when glowing plankton is most often found in many places. However, bioluminescence is notoriously hard to predict and can happen at any time. 

Most places that often see this chemical reaction concur that it happens in the middle to the late summer for the majority of the time.

You may also see bioluminescence around new moons as there is little to no moonlight that could make it harder to see the glowing organisms. 

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