Bioluminescence is the process of production and illumination with light by a living organism in the biosphere. It occurs mainly in marine organisms, both vertebrates, and invertebrates, and some terrestrial fungi and arthropods.
These organisms were famous since ancient times as a source of light but they attracted scientific curiosity only after Darwin observed luminous organisms that imparted green sparks when hit with waves. Scientists at that time made assumptions about how the organisms imparted light and many, including Darwin, summoned the light produced by the organism to be a disturbed electrical condition in the surrounding but none were able to search for the complex mechanism of how the light was produced inside a few of the existing organism’s body.
The answer to how is an organism able to synthesize light in their body was answered in the late nineteenth century only after a French pharmacologist carried out research work in bioluminescence and refuted the idea that this process of bioluminescence came from phosphorus. He proposed the idea that this process was a result of the oxidation of a specific compound called luciferin.
After years of research, it is believed that the actual functional role of bioluminescence in organisms was a reaction originally evolved to remove oxygen toxins from the environment and protect organisms that developed when their earth’s atmosphere has rarely any oxygen. Although, this condition has changed and oxygen is one of the most crucial reasons accounting for the flourishing organisms today, this metabolic process of oxygen reacting with an enzyme to produce light has evolved for other mechanisms in various organisms. The metabolic reaction is the combination of oxygen with a reducing substance called luciferin. This reaction liberated energy to excite molecules in the organism to emit visible lights. This process is found mostly among animals of lower groups like frogs, fungi, arthropods, crustaceans, algae, etc. This phytoplankton and algae are the reason that oceans seem to light up during a particular time of the year.
So, What causes bioluminescence in the water?
Walking on the shore is the most pleasing workout to go for in the morning or evening time, the rising sun during dawn and setting of the sun during dusk is the most spectacular view when observed from the shore of the ocean. Yet there’s more going on in the background of water after dusk, a phenomenon known as bioluminescence of water in the ocean is what really completes the puzzle of beauty and shine in the ocean.
Bioluminescence in the ocean water is not usually a rare phenomenon to occur it is a well-timed and precise chemical and biological reaction occurring in the living organisms in the push of natural force.
Bioluminescent dinoflagellates are a type of plankton that is responsible for illuminating the ocean water, therefore, giving shore a spectacular bioluminescence view. Also, fish, bacteria, and jellies are responsible for illuminating the ocean water. Illuminating dinoflagellates are mostly rare species and illuminate mainly due to luciferin-luciferase reaction. It is mostly found in the warm water and forms a close group with each other. It glows when being disturbed by waves which leads to a biochemical reaction in the body of plankton.
The purpose of illumination by the Bioluminescent dinoflagellates plankton is not yet been scientifically known but it is believed that:
1. It would scare the Predators.
2. Attracts the organisms that would consume or scare the predators.
3. It could just be a temporary bioluminescence phenomenon.
4. Conclusively, the reaction is occurring for survivability and adaptability.
The use of bioluminescence among animals has varied during evolution. More than half of the phyla in the animal kingdom division contains at least one member that can glow in the dark. This phenomenon, although common in the oceans, is also found in many lower terrestrial animals and plants.
Some of the common uses of bioluminescence in the ocean are :
1. Camouflage – The method of counter illumination is used by many organisms in the sea to camouflage against their predators. Their photoreceptors help to match the color of their environment overhead so that a predator from above can not see its prey. This is most commonly observed in squids.
2. Illumination – Sunlight cannot penetrate deep layers of the oceans and therefore there is no source of light there. A few fishes and organisms at great depth have adapted to this by producing their own light i.e bioluminescence. In deep oceans where light is almost absent, it is speculated that over 90% of the organisms are bioluminescent.
3. Attraction – Many species of bioluminescent help them attract their find food by attracting prey. Fishes like angler fish have evolved a dorsal fin that points its glowing dangle towards its mouth to attract prey in that area. This shine attracts prey as fecal matter, which is a staple food of many fishes, glow when they drift down. One particular species of the octopus also uses glowing lure. Its sucker shines with blue-green light which attracts copepods. Plants at the bottom of the ocean also attract their prey by imparting light.
4. Defense – Bioluminescent has also evolved to become a defense mechanism for aquatic organisms. This act of defense comes in various forms like startling prey, counter illumination, smoke screen, and misdirection. The lighting up of the sea by dinoflagellates is also a form of defense against predators. They shine when they detect a predator, which makes the predator vulnerable by attracting its predator from a high tropic region.
5. Communication – Communication is another use of bioluminescence by deep-sea organisms. It is in the form of quorum sensing. A fish called the flashlight fish uses bioluminescence to communicate with the male and attracts them for procreation. They have small pouches of bacteria under the eye. By opening and closing this pouch, the fish can communicate. These bacterias in some organisms can regulate the genes for light production according to the secretion of molecules and other factors in the environment. This communication method is also used by zooids to colonize effectively.
6. Mimicry – Bioluminescence is used by a variety of animals to mimic other species, especially in the deep-sea regions. Deep-sea organisms like dragonfish aggressively use mimicry to attract their prey by lighting up an appendage on their head. This glowing appendage lures smalls preys from a distance. Some species also mimic the light pattern of other prey to attract lure them towards themselves.
With the development of science and technology, bioluminescent is not only useful for animals but might also result in being one of the most useful things for humans. Scientists have been trying to infuse bioluminescence into bacterias, trees, and animals for purposes like tracking the progression of infections, alternate sources of light energy, etc.
As we try to incorporate bioluminescence into various aspects of our life, we are directed to one question.
Is bioluminescence harmful to humans?
And the answer is Maybe. In many seashores glowing blooms, humans can go for a swim or walk by the beach without any harm but some of the species of these dinoflagellates release a lot of toxins which might cause bowel problems or even neural toxicity.
These glowing blooms are generally observed during late summer and early fall: July to October. The tides are usually blue and red at the active bloom areas and are visible after dark. Some of the best places to observe this wondrous phenomenon are china, Puerto Rico, California, etc.
This glow lasts for a few hours after sunset and remains on the shore from anywhere between a few days to a few months. The organism has the power to illuminate themselves when needed until they die, but as these organisms leave the shore and migrate or die off, the glow in the seashore area is no longer seen.