Littoral refers to the coast of an ocean or sea, or to the banks of a river, lake or estuary. It is usually used as an adjective, but may also be used as a noun. The littoral zone extends from the high water mark, which is rarely inundated, to shoreline areas that are permanently submerged. It includes the intertidal and sublittoral zones. The word 'littoral' is derived from the Latin noun litus, litoris, meaning "shore". (The doubled 't' is a late mediaeval innovation and the word is sometimes seen in the more classical-looking spelling 'litoral'.)
In lakes, where tides are usually negligibly small, other definitions of "littoral" must be used. The Minnesota Department of Natural Resources defines littoral as that portion of the lake that is less than 15 feet in depth.[1] This zone is home to most of the aquatic plantlife (both rooted and floating) in a pond or lake because the high amount of sunlight reaching it allows for significant photosynthetic activity.
The adjacency of water gives a number of distinctive characteristics to littoral regions. Water's erosive power results in particular types of landforms, such as sand dunes, and estuaries. The natural movement of the littoral along the coast is called the littoral drift. Biologically, the ready availability of water enables a greater variety of plant and animal life, and the additional local humidity due to evaporation usually creates a microclimate supporting unique types of organisms.
The littoral zone is bordered by the supralittoral zone, also known as the "spray zone", and the sublittoral zone, which runs to the edge of the continental shelf.
Supralittoral zone
The supralittoral zone, also known as the spray zone, is the area above the spring high tide line that is regularly splashed, but not submerged by ocean water.
Sublittoral zone
The sublittoral zone starts immediately below the intertidal zone end extends to the edge of the continental shelf. It is permanently covered with seawater.
This zone is above the infralittoral zone and is separated into three zones.
This benthic zone is much more stable than the intertidal zone: temperature, water pressure, and the amount of sunlight remain fairly constant. Coral do not have to deal with as much change as intertidal zone organisms. They can live in both the intertidal zone and sublittoral zone. However they are more common in the sublittoral zone.
Although the sublittoral zone extends 200 m below sea level, plants and most animals stay in the upper 100 m, where sunlight reaches the ocean floor.
See also
References
- ^ "Fisheries lake surveys". Retrieved on 2006-03-17.
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