False Bay became a main attraction last week when those who had flocked to its shore witnessed a rare sight. It seemed the sea had reached up and plucked the stars from the sky, holding them captive beneath its surface. Captivated, the crowds took in nature’s light show which science has titled, “Bioluminescence.”
This lighting up of the waters happens as a result of algae reacting to calm and warm water. One can think of bioluminescence as a chemical reaction party where a light-making molecule (luciferin) meets an enzyme (luciferase). When they mingle, they create a burst of light, just like a tiny glowstick.
We, mere humans, get to witness this phenomenon when there is an excess of bioluminescence in the water, usually from an algae bloom of plankton. The bioluminescent sea will glow when disturbed by a wave breaking or a splash in the water at night.
Dr. Emma Rocke, a microbiologist and research fellow with the Marine and Antarctic Research Centre for Innovation and Sustainability (Maris) at the University of Cape Town, explained, “It is all completely natural. This phenomenon happens when the ocean is calm and warm. It is expected to happen at least once a year and lasts three to five days.”
According to Dr. Rocke, algae thrives and multiplies in calm and warm conditions. As they grow, they release bioluminescent compounds creating the glow we see in the water. This algal bloom benefits our ecosystem as it produces oxygen and consumes carbon dioxide.
She went on to say bioluminescence is connected to the red tide phenomenon. Red tide refers to the rapid multiplication of certain species of algae, often leading to discoloration of water. Seeing the red tide in the daytime would increase the probability of seeing bioluminescence in the evening if the environmental conditions remain the same.
Furthermore, the excessive presence of algae attracts prey, so we can expect to see more fish coming to do their groceries in the ocean during this time.
Here are some fun facts about bioluminescence:
- Bioluminescence is often referred to as “cold light.” This means that less than 20% of the light produced generates thermal radiation or heat chemistry.
- Some remarkable bioluminescent organisms can produce (synthesise) their own luciferin, the molecule responsible for creating light. It’s like they have their own built-in light show.
It’s important to note that some bioluminescent algae produce toxins that are harmful to marine wildlife, humans, and any creature in proximity. While the allure of swimming in the glowing waters may be strong, it is generally wiser to exercise caution and avoid such contact.
