The zone in the open ocean where light penetrates only to a depth of a few hundred meters is called the photic zone. This layer supports photosynthesis and is home to a variety of marine life, including phytoplankton and some fish species. Beyond this zone lies the aphotic zone, where light does not reach, making it dark and often inhabited by organisms adapted to those conditions.
The surface zone
200
Red light penetrates water the least, as it is quickly absorbed and scattered in the first few meters. Blue light, on the other hand, penetrates the deepest in water due to its longer wavelength.
There is no "usable" light agter 200 meters...
blue light penetrates the deepest in water
Red
It varies
Hagfish are deep-sea creatures that predominantly inhabit the aphotic zone, which is the deepest and darkest part of the ocean where little to no sunlight penetrates. They are typically found at depths ranging from a few hundred to several thousand meters below the surface.
The relationship between light and depth is primarily characterized by the way light intensity diminishes as it penetrates deeper into a medium, such as water or the atmosphere. This phenomenon, known as light attenuation, occurs due to scattering and absorption, which cause light to lose its intensity with increasing depth. In aquatic environments, for example, this leads to varying light conditions that affect photosynthesis and the overall ecosystem. Consequently, deeper areas receive less light, influencing the types of organisms that can thrive at different depths.
Oceans consist of 3 Zones, which are classified by the amount of light that passes through. The top two Ocean layers allow for sunlight to penetrate through, however NOT the third & deepest ocean zone. Euphotic Zone or 'Sunlight' Zone - Depth 200 Meters: The top most 200 meters of ocean is called the Euphotic Zone (or called the 'Sunlight' Zone). Sunlight travels easily throughout this Zone of the Ocean and plant-life flourishes in this Zone and is immensely widespread. Dysphotic Zone or 'Twilight' Zone - Depth 200 Meters - 1000 Meters: This layer, immediately beneath the Euphotic Zone/'Sunlight' Zone, between 200 meters and 1000 meters is called the Dysphotic Zone (or more commonly called the 'Twilight' Zone). Sunlight dissipates quickly as the depth increases, and very little light penetrates throughout this zone. Aphotic Zone or 'Midnight' Zone - Depth 1000+ Meters: The Aphotic Zone (sometimes called the 'Midnight' Zone), exists at depths below 1000 meters. No sunlight reaches this zone at all. It is completely absent of light; hence the slang term for it - 'Midnight' Zone.
blue
Light from the red end of the spectrum penetrates deep water better than light from the blue end of the spectrum. Evidence: Algae that live in deeper water have chlorophylls with absorbance peaks in the infra-red part of the spectrum.