Editing Photic zone (section)

== Life in the photic zone ==
[[File:Pelagiczone.svg|thumb|upright=0.74|right| Layers of the pelagic zone]]

[[File:Light penetration zones in the water column.png|thumb|upright=1.1|left| Zones of the water column as defined by the amount of light penetration. The mesopelagic is sometimes referred to as the ''dysphotic zone''.]]

Ninety percent of [[marine life]] lives in the photic zone, which is approximately two hundred meters deep. This includes phytoplankton (plants), including [[dinoflagellate]]s, [[diatom]]s, [[cyanobacteria]], [[coccolithophore]]s, and [[cryptomonad]]s. It also includes [[zooplankton]], the consumers in the photic zone. There are [[Carnivore|carnivorous]] meat eaters and [[herbivorous]] plant eaters. Next, [[copepod]]s are the small [[crustacean]]s distributed everywhere in the photic zone. Finally, there are [[nekton]] (animals that can propel themselves, like fish, squids, and crabs), which are the largest and the most obvious animals in the photic zone, but their quantity is the smallest among all the groups.<ref>{{Cite web|url=https://sciencing.com/trophic-levels-coral-reefs-5523723.html|title=Trophic Levels of Coral Reefs|website=Sciencing|access-date=2019-11-22}}</ref> Phytoplankton are microscopic plants living suspended in the water column that have little or no means of motility. They are primary producers that use solar energy as a food source.{{citation needed|date=January 2024}}

Detritivores and scavengers are rare in the photic zone. Microbial decomposition of dead organisms begins here and continues once the bodies sink to the aphotic zone where they form the most important source of nutrients for deep sea organisms.<ref>{{Cite web |title=Photic Zone - an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/earth-and-planetary-sciences/photic-zone |access-date=2023-11-27 |website=www.sciencedirect.com}}</ref> The depth of the photic zone depends on the transparency of the water. If the water is very clear, the photic zone can become very deep. If it is very murky, it can be only fifty feet (fifteen meters) deep.

Animals within the photic zone use the cycle of light and dark as an important environmental signal, migration is directly linked to this fact, fishes use the concept of dusk and dawn when its time to migrate, the photic zone resembles this concept providing a sense of time. These animals can be herrings and sardines and other fishes that consistently live within the photic zone.<ref>{{Cite web |title=Photic Zone - an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/earth-and-planetary-sciences/photic-zone |access-date=2023-12-01 |website=www.sciencedirect.com}}</ref>