You must have noticed the sparkle of fireflies in summer night or an ocean lit up at night with countless tiny flashes. This phenomenon, called bioluminescence, was also reported on the coast of Monterey bay of California but what causes this phenomena and from where does this light come from, was the first question every person had.
Bioluminescence is a basic chemical reaction that produces light energy in living organisms and demands the presence of two distinct chemicals. These two chemicals that are required for the chemical reaction to occur, are luciferin and luciferase where, luciferase acts as biocatalyst (enzyme).
Luciferin is a light-emitting molecule that functions as a substrate and reacts with oxygen in the presence of ATP. It is responsible for producing different types of light in these organisms such as yellowish in fireflies and green in lantern fish. On the other hand, luciferase acts as an enzyme to increase the rate of the reaction. (E. Widder, ORCA) Some species even combine luciferin with oxygen to form a “photoprotein” which functions as a ready-to-light bioluminescence bomb when a certain ion, usually calcium, is present.
Some organisms do not produce luciferin, e.g. angler fish rely on other organisms called symbionts to produce bioluminescence. They do so either by coming in contact with the bacteria and assimilating them or through direct transmission from other individuals. Small fishes that haven’t yet mastered the power of bioluminescence are drawn to the esca, which contains bacteria that generate light via the aperture of their mouth and thus attracting predators. Since, angler fish can’t shine, it holds the bacteria in esca (William J. Broad, 2019).
Some bioluminescent animals, such as fireflies, can be found on land, but the vast majority of them live in the water and generate blue-green light, because these are shorter wavelengths, they scatter the most and hence can reach the deepest levels. For instance, Dinoflagellates, which are a form of plankton and share both plant and animal features, emit a bluish-green bioluminescence. Around 90% of dinoflagellates don't create much light if left alone, but can produce a lot if the conditions are perfect, such as ocean waves, currents, or human disturbances. In the Humacao Natural Reserve in Puerto Rico, biologists discovered a new bioluminescent dinoflagellate ecosystem in 2010.
Benjamin Franklin speculated in 1753 that some type of “very tiny animalcule” in water “may yet emit a visible light”. Around the same time, naturalists like Godeheu de Riville, armed with early microscopes, verified Franklin’s hunch: the ocean’s glints and glows came from living things, from microscopic “marine insects”, we now refer to as plankton.
In 1995, a British captain recorded a description of the whitish glow in the sea in his ship’s logbook. However, there were no pictures or proofs available, which piqued the interest of many marine scientists. One of them was Steven Haddock, who received confirmation of such a whitish glow of the ocean from space, covering 300km of the area, but the question remained as to what was causing such a white glow that could be seen from space. There are bacteria that feed on algal blooms, and when they reach a particular level, they glow, causing practically every living organism in the area to shine as well.
The power of bioluminescence requires lots of energy, so the question comes, why organisms use such amount of energy. According to scientists, living organisms utilise bioluminescence to hunt prey, defend against predators, find mates, e.g. The male Caribbean Ostracod, a tiny crustacean, attracts females with bioluminescent signals on its upper lips. Also, the bright signal might shock and distract the predator, causing it to become confused about where its victim is. With the use of counter illumination, bioluminescence may also be used to aid with camouflage (Smithsonian Institution). This is how they save themselves. When the deep sea shrimp Acantherphyra purpura feels threatened, it spews a glowing slime from its mouth, and everyone flees the other way except those who have just puked on them. Moreover, the puke attracts larger predators that consume the shrimp opponent (Bioluminescence, National Geographic).
Bioluminescence fascinates the Navy too. Items moving across the ocean can cause bioluminescent organisms to flash. The service wants to “create a navigation assist for underwater vehicles that will sense any bioluminescence produced” and indicate whether an opponent may see the light and, as a result, detect the vehicle.
When scientists discovered how bioluminescent creatures create luciferase and luciferin through genetic engineering, they transplanted these chemicals' genes to a healthy tobacco plant, which then lit up like a Christmas tree. For example, the green fluorescent protein (GFP) is a useful "reporter gene." Biologists use reporter genes to link substances (genes) to other genes they're studying. The fluorescence of GFP reporter genes allows them to be easily identified and quantified. (In 2008, along with Martin Chalfie of Columbia University and Roger Tsien of the University of California, San Diego)
Scientists are developing trees that can lit up. They can come to different use to humans. In the future, this technology could be used to non-invasively visualise the activity of several hormones inside plants during the course of their lives in various tissues. It can also be used to track how plants react to different stresses and changes in the environment, such as drought or herbivore injury. (Dr. Karen Sarkisyan, the CEO of Planta)
Amazing!!!