I have to be honest with you: when I first saw a photo of a glowing beach in the Maldives I thought it was the result of heavy editing. It was too beautiful to be real; it looked like a scene from Avatar.
Of course, I knew what bioluminescence was. I studied it in detail during my master’s degree, but no professor or marine biology book had ever told me it could be that intense.
After moving to the Maldives I soon realized that it was all real.
What is bioluminescence?
Bioluminescence is the emission of light by a living organism through a chemical reaction. In the ocean, this is commonly observed in deep-sea creatures that, living in the dark, use it as a form of communication. Deep-sea animals are not the only ones who master the production of light. In fact, bioluminescence occurs in several organisms at all depths and it’s used for different purposes.
Ok, this is very interesting but what makes the beach glow?
Among these organisms, there are some species of Dinoflagellates and Ostracods, tiny planktonic creatures (phytoplanktonic and zooplanktonic, respectively) that produce light when disturbed. In this case, bioluminescence is a defense mechanism that acts as a burglar alarm. When a flash is triggered by contact with a grazer/predator, it attracts a higher-level predator that will consume the grazer/predator and set the bioluminescent prey free. Moreover, these bright flashes disorientate the predator, disrupting its feeding behaviour.
In certain conditions, bioluminescent plankton becomes abundant in the water and put on a wonderful light show at night, where the waves break onto the beach. If the sea is too calm and the waves are just gently lapping the beach, this may not be enough to trigger bioluminescence. In this case, you can find a dark spot on the beach, agitate the water with your feet and let the magic happen.
Why doesn’t this phenomenon happen year-round?
Being planktonic, these bioluminescent organisms drift with the currents and don’t stay in one place for too long. Moreover, the conditions that cause them to bloom and light up the shore occur only at certain times of the year.
I’ve been lucky enough to witness this stunning phenomenon several times and yet it amazes me every single time. Definitely a bucket list experience.