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The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth. From the point of view of
marine biology Marine biology is the scientific study of the biology of marine life, organisms in the sea. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies ...
it forms a relatively stable and well-illuminated environment for marine life, from plankton up to large fish and corals, while physical oceanography sees it as where the oceanic system interacts with the coast.


Definition (marine biology), context, extra terminology

In
marine biology Marine biology is the scientific study of the biology of marine life, organisms in the sea. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies ...
, the neritic zone, also called coastal waters, the coastal ocean or the sublittoral zone, refers to that zone of the ocean where sunlight reaches the
ocean floor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...
, that is, where the water is never so deep as to take it out of the
photic zone The photic zone, euphotic zone, epipelagic zone, or sunlight zone is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological pro ...
. It extends from the low tide mark to the edge of the continental shelf, with a relatively shallow depth extending to about 200 meters (660 feet). Above the neritic zone lie the
intertidal The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species of ...
(or eulittoral) and supralittoral zones; below it the
continental slope A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental margin ...
begins, descending from the continental shelf to the
abyssal plain An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between and . Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth's surface. T ...
and the pelagic zone. Within the neritic, marine biologists also identify the following: * The infralittoral zone is the
algal Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular micr ...
-dominated zone down to around five metres below the low water mark. * The circalittoral zone is the region beyond the infralittoral, which is dominated by
sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...
animals such as oysters. * The subtidal zone is the region of the neritic zone which is below the intertidal zone, therefore never exposed to the atmosphere.


Physical characteristics

The neritic zone is covered with generally well- oxygenated water, receives plenty of sunlight, is relatively stable temperature, has low water pressure and stable salinity levels, making it highly suitable for photosynthetic life. There are several different areas or zones in the ocean. The area along the bottom of any body of water from the shore to the deepest abyss is called the
benthic zone The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...
. It is where decomposed floral and faunal debris (also known as ocean 'snow') has settled to form a sediment layer in which various plants can grow. All photosynthetic life needs light to grow and how far out into the ocean light can still penetrate through the water column to the floor or
benthic zone The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...
is what defines the neritic zone. That
photic zone The photic zone, euphotic zone, epipelagic zone, or sunlight zone is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological pro ...
, or area where light can penetrate through the water column, is usually above ~100 meters (~328 feet). Some coastal areas have a long area of shallow water that extends far out beyond the landmass into the water and others, for example islands that have formed from ancient volcanos where the 'shelf' or edge of the land mass is very steep, have a very short neritic zone.


Life forms

The above characteristics make the neritic zone the location of the majority of sea life.Office of Naval Research
The result is high primary production by photosynthetic life such as phytoplankton and floating sargassum;
zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...
, free-floating creatures ranging from microscopic
foraminiferans Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly a ...
to small fish and shrimp, feed on the phytoplankton (and one another); both
trophic levels The trophic level of an organism is the position it occupies in a food web. A food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the number of steps it i ...
in turn form the base of the
food chain A food chain is a linear network of links in a food web starting from producer organisms (such as grass or algae which produce their own food via photosynthesis) and ending at an apex predator species (like grizzly bears or killer whales), det ...
(or, more properly,
web Web most often refers to: * Spider web, a silken structure created by the animal * World Wide Web or the Web, an Internet-based hypertext system Web, WEB, or the Web may also refer to: Computing * WEB, a literate programming system created by ...
) that supports most of the world's great wild fisheries. Corals are also mostly found in the neritic zone, where they are more common than in the
intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species of ...
as they have less change to deal with.


Definition (physical oceanography)

In physical oceanography, the sublittoral zone refers to coastal regions with significant tidal flows and energy dissipation, including
non-linear flow In mathematics and science, a nonlinear system is a system in which the change of the output is not proportional to the change of the input. Nonlinear problems are of interest to engineers, biologists, physicists, mathematicians, and many other ...
s,
internal wave Internal waves are gravity waves that oscillate within a fluid medium, rather than on its surface. To exist, the fluid must be stratified: the density must change (continuously or discontinuously) with depth/height due to changes, for example, in ...
s, river outflows and ocean fronts. As in marine biology, this zone typically extends to the edge of the continental shelf.


See also

*
Coastal fish Coastal fish, also called inshore fish or neritic fish, inhabit the sea between the shoreline and the edge of the continental shelf. Since the continental shelf is usually less than deep, it follows that pelagic coastal fish are generally epi ...


References

{{Biomes Aquatic ecology Fisheries science Physical oceanography Aquatic biomes Oceanographical terminology