Bioluminescence

Bioluminescence is the ability to produce light by some organisms. The example of bioluminescence in animals includes jellyfish, squid, and phytoplankton. Bioluminescence is created through a chemical reaction involving luciferins and an enzyme called luciferase, along with oxygen. When these substances combine, light is emitted. Bioluminescence serves different purposes, such as attracting mates, luring prey, or scaring off predators. In this article, we will look into the meaning of Bioluminescence, examples, mechanisms, and applications of Bioluminescence.

What is the Meaning of Bioluminescence?

Bioluminescence is a form of chemiluminescence that enables living organisms to create their light. The word “bioluminescence” stems from “bio-” meaning life and “lum” or “lumin” from the Latin words lumen or lux, denoting light. This phenomenon is widely distributed in nature, from the terrestrial surface of the earth to the ocean floor.

From the sparkling sea water along the shoreline to the glowing lure of anglerfish in the dark as well as the flickering signals of fireflies, all these are outcomes of this remarkable phenomenon. Bioluminescence results from a chemical reaction where chemical energy is converted to light energy with utmost efficiency. Less than 20% of the bioluminescent light is given off as thermal energy or heat and hence is sometimes termed as ‘cold light’.

Bioluminescence Animals

Bioluminescence refers to the ability of living creatures to emit light. Here are a few examples of bioluminescent animals:

• Insects with Bioluminescence: Fireflies.
• Aquatic animals with Bioluminescence: Jellyfish, Anglerfish, Dragonfish.
• Microbes with Bioluminescence: Dinoflagellates, Fungi.

Mechanism of Bioluminescence with Diagram

Bioluminescence is a result of an enzymatic reaction, which includes an enzyme called luciferase and its substrate, a group of small molecules known as luciferins. Luciferase actually speeds up the chemical reaction between luciferins and oxygen. During this reaction, luciferins are oxidised to form a new molecule, oxyluciferin, with emission of light in the form of bioluminescence. Afterward, luciferase is recycled, and the reaction continues as long as both luciferin and oxygen are present.

Main Purpose of Bioluminescence

Light production seems to be associated with various survival aspects of a species:

• For Defence: Bioluminescent organisms use bioluminescence in various defence mechanisms such as startling prey, counterillumination, burglar alarm, or warning coloration. The shrimp family Oplophoridae Dana uses bioluminescence to startle predators. When disturbed, dinoflagellates also flash to scare away their predators.
• As Warning: Bioluminescence in some creatures can serve as a warning, known as aposematism. The aquatic snail Latia neritoides uses greenish luminescent mucus to deter predators, endorsing it as unpalatable or potentially harmful.
• To Attract Prey: Deep sea fishes tend to use bioluminescence to attract prey. For example, the anglerfish have a special appendage on their heads called an esca, which contains bioluminescent bacteria. This esca glows in the dark, helping the fish lure the small animals towards it.
• For Mating: Fireflies produce light to attract mates. Male fireflies looking for mates flash a pattern of light that is species-specific to let females know they are ready to mate.
• For Camouflage: Bioluminescence helps animals blend in by matching the background brightness, called counterillumination. The Hawaiian bobtail squid has a light organ with bioluminescent bacteria that helps it match the brightness and colour of the sea surface above.
• For Illumination: Some deep sea fishes (such as dragonfish) exhibit relatively rare red bioluminescence. This helps them to see red-pigmented prey which are normally invisible to other creatures in the deep ocean.
• Mimicry: Some animals use bioluminescence to mimic other species. For example- female Photuris fireflies mimic the light pattern of female Photinus fireflies to attract males as their prey.

What is an Example of Bioluminescence in Animals?

Bioluminescence is rare on land but common in the sea. Here are some of the organisms that exhibit bioluminescence:

• Fireflies: All fireflies belong to a group of insects called beetles. The luciferin-luciferase reaction occurs in a light-producing organ in their abdomen. Adult fireflies use bioluminescence to find mates. Males and females of the same species show a special flash pattern to communicate before mating. Conversely, firefly larvae use their light to warn predators not to eat them.
• Jellyfish: More than half of jellyfish species can bioluminesce to scare away predators. Some even release glowing mucus to confuse their attackers. Aequorea victoria, also known as the crystal jelly, exhibits a green glow around its rim due to the presence of green fluorescent protein (GFP).
• Anglerfish: Anglerfish live in the deep ocean where sunlight cannot reach. They have a long appendage on their head called the esca, which contains bioluminescent bacteria. The esca acts as a glowing lure for small fishes. Sea creatures are attracted to this dangling esca and get devoured by the anglerfish.
• Dinoflagellates: The glowing neon blue light in the ocean waters and shores are caused by dinoflagellates. Dinoflagellates are single-celled phytoplanktons that grow in warm seawaters. They normally luminesce at night and when disturbed. These algae defend themselves by flashing to startle and scare off their predators. The bioluminescence might also attract larger predators to eat their own attackers, acting like a burglar alarm that alerts the police to catch a robber at someone’s house.
• Dragonfish: Deep-sea dragonfish are unique because they can make and see red light. They live in the bathyal zone, where hardly any sunlight reaches, making it really dark. With their red bioluminescence, they can find prey and approach without being seen, as they can see red light that other sea creatures cannot.
• Fungi: Some fungi are also capable of producing light. Over 70 species of fungus can bioluminesce. Unlike other bioluminescent creatures, they glow all the time. The brightest glowing fungi are mostly found in tropical areas. Fungi might glow to scare away predators or to attract insects that spread their spores. Example: Jack-o-lantern mushroom (Omphalotus olearius).

Uses of Bioluminescence

Bioluminescent proteins are extensively used in biotechnology:

• Luciferase can be used as reporter genes in genetic engineering to track gene expression and activity. Bioluminescence imaging techniques utilise GFP to monitor biological processes such as protein function and interactions.
• The light-producing organs of the bioluminescent organisms are investigated for the development of sustainable light sources for the future.

Conclusion – Bioluminescence

Bioluminescence is a natural phenomenon found in various organisms, from marine creatures like jellyfish to land entities like fireflies. It serves essential purposes such as attracting mates, deterring predators, luring prey and camouflage. Bioluminescence results from an enzymatic reaction involving luciferase and luciferins. The discovery of Green Fluorescent Protein has proved beneficial because it serves as a valuable tool in biotechnology. GFP can be used to monitor important biological processes, enabling advancements in genetic engineering and biomedical research.

Also Read:

• What are Protists?
• Chrysophytes
• Kingdom Protista

FAQs on Bioluminescence

What is Bioluminescence Class 11 Biology?

In Class 11 Biology, bioluminescence is the emission of light by living organisms through biochemical reactions, commonly observed in marine organisms like plankton and jellyfish, serving various ecological roles.

When was the First Discovery of Bioluminescence?

Aristotle made the first discovery of Bioluminescence.

Is Bioluminescence Visible Light?

Yes, bioluminescence is a chemical process that produces visible light within living organisms. Bioluminescence is mostly expressed in the blue-green range of the visible light spectrum.

Which Algae causes Bioluminescence?

Unicellular marine algae named Dinoflagellates, are usually responsible for surface water luminescence. Example- Noctiluca scintillans, commonly known as sea sparkle is one of such microalgae.

What are the Bioluminescent Beaches in India?

There are several bioluminescent beaches in India, namely Mattu beach in Karnataka, Radhanagar beach in Havelock island, Bangaram island beach in Lakshadweep, Thiruvanmiyur beach in chennai, Varkala beach in Kerala etc.

Is Bioluminescent Water Safe?

While some bioluminescent water bodies are safe for human activity, others containing toxic algae like Noctiluca sp and Lingulodinium sp etc. are considered dangerous for swimming.

What is the Brightest Bioluminescent Animal?

Pyrophorus noctilucus, also known as the headlight elater or Cucuyo, is one of the biggest bioluminescent insects with highest surface brightness of 45 millilamberts.

What are Bioluminescence Planktons?

Bioluminescent plankton are tiny marine organisms that emit light, creating a natural phenomenon when disturbed, often observed in ocean waters during the night.

Which Phylum has Bioluminescence?

Bioluminescence is found in various phyla, but notably in the phylum Cnidaria, which includes jellyfish, corals, and other aquatic animals.