Bioluminescence – mysterious light in the ocean

In the depths of the ocean, where the sun’s rays do not reach, there is, as one might expect, absolute darkness. However, if we could plunge into these abysses, our eyes would see a fascinating view reminiscent of the night sky full of twinkling stars. This surprising phenomenon is bioluminescence, the ability of many marine organisms to produce and emit their own light. They create beautiful and unusual lightscapes that are a source of constant amazement for researchers and nature lovers.

Bioluminescence – where does the light come from?

Bioluminescence is the ability of organisms to produce and emit light through biochemical reactions. It is common in the marine world, but also occurs in some terrestrial organisms, including skylights and fungi. Bioluminescence is based on a chemical reaction between two substances: luciferin and luciferase. Luciferin is a molecule that, when combined with luciferase, undergoes a chemical reaction under the influence of oxygen and releases energy in the form of light. The effect of this process is visible as a flickering, glowing or flashing light of different colors, usually blue-green or yellow-orange. The appearance of bioluminescent light varies depending on the habitat and organism in which it is found.

Marine organisms have the ability to control the bioluminescence process to use it at the right times. They can do this by regulating oxygen access to cells containing luciferin and luciferase. For example, by constricting or dilating blood vessels, they control blood flow and thus the amount of oxygen delivered to photophores – special light organs. With this ability, animals can save energy and use light only when necessary.

Bioluminescent organisms use this type of light for various purposes. One of the main reasons is interspecies communication, and light is a signal for partners to find each other for reproduction. Bioluminescence can also play a defensive role, diverting the attention of predators. Some organisms use bioluminescence for food (as a lure to attract prey) and as camouflage, adapting their light to the surrounding environment, making them harder to detect.

Starfish, shrimp and squid – the most famous bioluminescent creatures

The ocean is home to many species of animals that exhibit the ability to produce and emit their own light. Starfish have numerous luminous glands that, when stimulated, can flicker, creating the sensation of pulsating light. Shrimp are known for causing spectacular light waves. And squid, with the help of their photophores, emit different colored light, which allows them to camouflage, communicate and hunt effectively.

Bioluminescence, however, is not limited to these groups. Many species of fish and jellyfish show abilities in this direction. Even worms or sea cucumbers can produce their own light, which adds mystery and magic to this deep-sea environment. It is worth noting that not all organisms produce their own luciferin and luciferase. Some of them acquire these molecules by consuming other bioluminescent organisms.

The magic of luminous microorganisms – phytoplankton and bioluminescent bacteria

Bioluminescence is not just limited to larger creatures. Microscopic organisms such as phytoplankton and bacteria can also produce light. Phytoplankton have the ability to bioluminescence and create beautiful light waves at night, popularly known as a “sea of stars.” Bioluminescent bacteria, which occur in symbiosis with some animal species, also play an important role in marine ecosystems.

They live in the host, in special organs or tissues of the host, such as photophores or bladders, which provide them with suitable conditions for existence. The host provides nutrients, as well as protection from the external environment, which enables the bacteria to survive and grow. In return, they shine if the host needs it. When an animal wants to emit light, it regulates the access of oxygen to the bacteria or controls other factors that stimulate the bioluminescence process. As a result, the bacteria start a chemical reaction in which light is triggered.

Human impact on ocean bioluminescence

Unfortunately, human activity is having a negative impact on the ocean’s bioluminescence. A particular problem is artificial light pollution, which results from excessive lighting of coastal areas and light emitted by ships. These artificial light sources interfere with natural bioluminescence and affect the functions of organisms in this area, hindering their communication, camouflage and ability to feed. Another threat is ocean pollution. Chemical spills and the presence of plastic waste in the ocean can disrupt processes and pose a direct threat to marine organisms.

These negative human impacts on the ocean’s bioluminescence are a serious problem because they upset the delicate balance and function of marine ecosystems.

Bioluminescence – how to protect this fascinating phenomenon?

It is important to protect the bioluminescence of the ocean from the negative effects of human activities in the first place. Reducing artificial light pollution, introducing appropriate regulations for ships and limiting water pollution are key to protecting this beautiful phenomenon. In addition, education and public awareness play an important role in promoting sustainable management of marine ecosystems. Preserving this unique oceanic heritage is not only important for marine organisms, but also for the inspiration we get from the mysterious light in the ocean depths.