Description of the image: the Atolla jellyfish, which lives in the shadow biosphere, produces light to attract its prey.
The "shadow biosphere" refers to a specific zone within aquatic ecosystems, particularly in oceans, where solar light does not penetrate sufficiently. This region lies in the ocean depths, where sunlight is filtered and attenuated by the upper water layers.
The "shadow zone" is a term often informally used to describe this specific part of the ocean.
To understand in more detail, it is necessary to examine how light behaves in water.
When sunlight enters seawater, it is absorbed and scattered by water molecules, suspended particles, and dissolved substances. This absorption and scattering of light lead to a gradual decrease in light intensity with depth. As a result, visible light is absent below a certain depth.
There is a physical relationship between brightness and depth in water. It can be described by the Beer-Lambert law. This law is a mathematical expression that describes the attenuation of light as it passes through an absorbing medium, such as seawater.
This equation shows that light intensity decreases exponentially with depth in water.
I(z)=I0 . e−k⋅. z
• I(z) is the light intensity at a certain depth.
• z is the depth at which light intensity is measured.
• I0 is the light intensity at the water surface.
• e is the mathematical constant Euler's number, approximately equal to 2.71828.
• k is the coefficient of light absorption by water, with an average value of k≈0.1m−1 (the coefficient of light absorption by water is 0.1 per meter).
Both the shadow biosphere and the abyss are terms used to describe specific zones in the oceans, but they refer to slightly different aspects of marine environments. While the shadow biosphere and the abyss are both associated with ocean depths and low-light conditions, the shadow biosphere specifically focuses on the reduction of solar light at depths where photosynthesis becomes difficult, whereas the abyss refers to the deepest and least explored regions of the ocean.
Above the shadow biosphere lies the upper pelagic zone, also known as the epipelagic or photic zone. It corresponds to the part of the ocean where solar light penetrates sufficiently to allow photosynthesis. This zone is characterized by adequate brightness for the growth of phytoplankton and the development of the marine food chain. It is where most marine organisms that rely on light for sustenance, such as fish, marine mammals, crustaceans, and many other organisms, are found.
Below the upper pelagic zone is the middle pelagic zone, where brightness gradually decreases with depth. This zone is also called the mesopelagic zone. Although it is less bright than the upper pelagic zone, it still supports a variety of organisms adapted to low-light conditions.
Below the middle pelagic zone is the deep pelagic zone, or bathypelagic zone, where light is very limited or absent. This region generally corresponds to the shadow biosphere, where photosynthesis is no longer possible due to insufficient solar light. It is in this zone that organisms adapted to low-light conditions or alternative energy sources, such as bioluminescent organisms and chemosynthetic communities near hydrothermal vents, are found.
The region where sunlight becomes insufficient for photosynthesis is called the "aphotic zone" or "shadow zone". In this region, photosynthesis, which is the process by which organisms produce energy from solar light, is no longer possible because there is not enough light to support this process.
However, although solar light is limited in the shadow biosphere, there are still life forms that adapt to it. These organisms often have special mechanisms to obtain energy and survive in low-light conditions. For example, some species of deep-sea fish have bioluminescent organs that emit light for hunting, communication, or camouflage. Additionally, there are complex biological communities that develop around hydrothermal vents in the ocean depths, where microorganisms derive their energy from chemical processes rather than sunlight.
Oceanic zones are classified into different layers based on depth and environmental conditions, including light and pressure.
• Epipelagic Zone (or photic zone): 0 - 200 m
• Mesopelagic Zone (or twilight zone): 200 - 1,000 m
• Bathypelagic Zone: 1,000 - 4,000 m
• Abyssopelagic Zone (or abyssal zone): 4,000 - 6,000 m
• Hadopelagic Zone (or hadal zone): 6,000 - 11,000 m
The shadow zone begins in the mesopelagic zone and includes the bathypelagic and abyssopelagic zones. Each zone presents unique environmental conditions that select for biodiversity and adaptations of marine organisms living there.
Why Did the Genus Homo Nearly Go Extinct 900,000 Years Ago? 
AlphaGo vs AlphaGo Zero: A Revolution in Artificial Intelligence 
The Next Step for Intelligent Machines 
The First Step Towards the Emergence of Life 
Phylogenetic Tree of Life 
Formal neuron 
Decline of Anthropocentrism 
Artificial intelligence: the explosion of gigantism 
When AI models train on their own data, they go mad! 
Emergence of artificial intelligence: Illusion of intelligence or intelligence? 
The
horseshoe crab, a living fossil! 
Biosignatures or presence of life in the Universe 
Challenge and threat of Artificial Intelligence 
How do machines understand, interpret and generate language in a similar way to humans? 
How does an artificial neural network work? 
Origin of life on Earth: Panspermia theory 
Origin of life on Earth: White smoker theory 
Why 37 degrees Celsius? 
Thermodynamics of the sandpile 
Are we alone in the universe? 
Trace of frozen life in Siberia 
Ice cores tell us about our past 
Life evolves in the shelter of glaciations 
Organ regeneration, the salamander 
Cosmic rays and the mutation of species 
Mephisto, the little worm of the depths 
Discovery of solid buckyballs in space 
Bipedalism in
hominids 
Kamchatka
giant crab 
The passage between the inert and the living 
From particles to biochemical life 
Egocentric vision, the man at the center 
Megapod
uses volcanic heat 
Ardi is 4.4 million years old 
Natural selection, the birch moth 
The explosion of life in the Ordovician 
Liquid water, an accelerator of chemical reactions 
Neandertal 
Asimo the
future humanoid 
Conditions for the appearance of life 
Fermi's paradox or Plato's cave 
The Tardigrade, the immortal animal 
Toumaï,
7 million years old 
Border between inanimate and living 
The incredible life of the abyss 
Cyanobacteria create toxic gas 
The short history of the evolution of life 
The smallest frog in the world 
The explanation of the Little Ice Age 
Ashen light, the proofs of life 
Bioluminescence
of living organisms 
Beyond our senses, the great scientific revolutions 
The primitive
soup