Understanding bioluminescence and observing it in the wild
Bioluminescence is a fascinating natural phenomenon in which living organisms produce and emit light. This captivating glow is the result of a chemiluminescence reaction, where chemical energy is converted into radiant energy in the form of visible light.
Bioluminescence can be observed in an incredible diversity of creatures, from the flashes of deep-sea fish and the trails of marine invertebrates to the flickers of fireflies and the shine of certain mushrooms. Humans primarily observe the bioluminescence of dinoflagellates in waters that have been physically disturbed, usually by the crashing of waves or the movement of a watercraft.
In this article, we’ll explain exactly what bioluminescence is and its function. We’ll also share with you some of the best places to witness it in the natural world, including on our guided kayaking adventures.
What is bioluminescence?
Bioluminescence is the result of a chemical reaction that takes place within an organism's body. In some cases, the luminescence originates from symbiotic bacteria residing within the host organism, such as the Vibrio bacteria that form a mutually beneficial partnership with many marine animals. Other creatures, however, have evolved the ability to produce their own light completely autonomously through specialized organs called photophores.
When the chemical reaction takes place, a compound called luciferin is oxidized by an enzyme known as luciferase, releasing energy in the form of light. The color of the light produced can vary depending on the specific chemical structure of the luciferin and luciferase involved.
Animals have the ability to manage their bioluminescence by adjusting their chemical reactions and brain functions based on their current requirements, such as finding food or attracting a mate. Some species even create a "photoprotein," which combines luciferin with oxygen, functioning like a ready-to-use bioluminescent device that activates when specific ions are detected. Additionally, they can select the brightness and hue of their glow to meet their needs.
Which animals produce bioluminescence?
Bioluminescent creatures are found in a wide range of habitats, from the depths of the ocean to terrestrial environments. The sheer diversity of bioluminescent life is truly astounding, with over 700 animal genera documented to contain light-producing species.
In the marine world, bioluminescence is particularly prevalent, with an estimated 80-90% of deep-sea animals possessing this ability. In coastal marine environments, it is estimated that around 2.5% of organisms have the capacity to produce light, including several species of fish, crustaceans, and cephalopod mollusks.
Perhaps the most commonly encountered bioluminescent organisms are the dinoflagellates, microscopic phytoplankton that populate the surface layers of the ocean. These tiny creatures are responsible for the sparkling luminescence that can sometimes be observed at night when shallow water is disturbed. At least 18 genera of dinoflagellates are known to exhibit this luminous quality, many of which thrive in warm water lagoons and bays with restricted access to the open ocean.
The majority of marine bioluminescence is characterized by blue and green hues, as these wavelengths travel furthest through seawater. However, there are exceptions, such as some species of loose-jawed fish that emit red and infrared light, and the marine worm genus Tomopteris, which produces a yellow glow.
On land, fireflies are perhaps the most well-known bioluminescent organisms, using their captivating light displays for communication and to attract mates. It also occurs in certain species of fungi and bacteria, as well as in various terrestrial invertebrates, with beetles being the most notable examples.
What is the function of bioluminescence in nature?
Scientists believe that bioluminescence has multiple functions in different taxa, however, it’s easier for them to detect that a species can produce light than prove what function the light serves. In many deep-sea animals, it is thought to be used for camouflage by counterillumination, with the animal matching the brightness of the natural light streaming in from above.
On land, fireflies use light to attract mates and this is echoed in the bioluminescence of ostracods (shrimp-like crustaceans) in the marine environment. Female Bermuda fireworms also light up following the full moon in a bid to attract males.
Bioluminescence can also be used as a form of defense to startle prey or serve as a smoke screen. At least 70 genera of squid are bioluminescent, with some expelling a cloud of luminescent material to distract or repel predators.
Amongst zooids (single animals that form part of a colonial animal), the emission of light is used for communication, helping to synchronize collective efforts. Bioluminescence is also used by some species as a form of mimicry, as exhibited in anglerfish. Their luminescent fin rays lure small marine animals, bringing them within striking distance.
Bioluminescent kayaking
One of the best ways to experience bioluminescence is while kayaking, as the movement of the paddle through the water triggers the chemical reaction in the dinoflagellates that produces light. Bioluminescent kayaking provides a wonderful opportunity to learn more about this natural phenomenon and understand its process while witnessing it in real-time.
The ideal time for bioluminescent kayaking is on moonless or cloudy nights, in a more remote setting, with little-to-no light pollution from urban areas. It’s best observed in sheltered bays and lakes, particularly after heavy downpours following a period of no rain. That being said, bioluminescence can appear anywhere and at any time - sometimes you just have to be lucky!
The best places to see bioluminescence around the world
There are numerous locations across the globe where bioluminescence occurs in shallow waters, making it easily visible to humans on land or in watercraft. One of the most famous spots is Mosquito Bay in Vieques, Puerto Rico, where microscopic dinoflagellates light up the water when disturbed. Another top destination is the Luminous Lagoon in Jamaica, home to millions of bioluminescent microorganisms that give the shallow waters an otherworldly gleam.
In Southeast Asia, Thailand's Ang Thong National Marine Park features dazzling displays of glowing plankton, best viewed during a nighttime boat tour or kayak. Other incredible locations to witness bioluminescence include Toyama Bay in Japan, where firefly squid emit a blue light;, and the mangrove lagoons of the Maldives, which are inhabited by glowing ostracod crustaceans.
Bioluminescence is regularly observed by kayakers exploring the calm bays of Vancouver Island in British Columbia, with the summer months of July and August usually offering the best sightings. The warm water temperatures and calm conditions provide an ideal environment for the dinoflagellates to flourish.
Our guests have also observed bioluminescence while kayaking in the shallow waters of Baja California. The 2020 bioluminescence event was particularly impressive, lasting for around six weeks and seeing the Pacific Ocean lit up all the way from Cabo San Lucas to Los Angeles.
For a different perspective, you can head to Waitomo in New Zealand, where thousands of bioluminescent glowworms illuminate the ceilings of caves, creating the illusion of a star-filled night sky.
The best time to observe bioluminescence
Generally speaking, the best time to witness bioluminescence is on a moonless night, preferably a few hours after sunset when the sky is at its darkest. Overcast nights are ideal, as any ambient light from the moon or nearby urban areas will be minimized, allowing the bioluminescence to really shine.
Interestingly, the few days following stormy weather and rainfall can often lead to especially vivid displays. The rain washes nutrients from the land into coastal waters, acting as a natural fertilizer for the marine phytoplankton responsible for these light shows. This influx of nutrients can trigger blooms of the microscopic organisms, resulting in especially bright and mesmerizing displays.
The ongoing study of bioluminescence
The study of bioluminescence has not only shed light on the adaptations of many organisms but has also led to significant advancements in biotechnology, medicine, and environmental monitoring. In biotechnology, bioluminescent proteins have revolutionized how researchers visualize and track biological processes at the cellular and molecular level, enabling groundbreaking discoveries in genetics, cell biology, and drug discovery.
Medical applications have harnessed bioluminescence for highly sensitive diagnostic tools, such as detecting cancer cells and monitoring the progression of infections, offering earlier detection and more targeted treatments. Additionally, bioluminescent organisms serve as invaluable indicators of environmental health, with changes in their light output signaling shifts in water quality, pollution levels, or ecosystem dynamics.
