Editing Littoral zone (section)

==In oceanography and marine biology==
[[File:Olympic Coast National Marine Sanctuary.jpg|thumb|The littoral zone of an ocean is the area close to the shore and extending out to the edge of the continental shelf.]]
[[File:Portugal 20040711 027.jpg|thumb|right|The [[intertidal zone]] of a beach is also part of the littoral zone.]]
[[File:Klamath river estuary.jpg|thumb|right|[[Estuary|Estuaries]] are also in the littoral zone.]]
{{wiktionary|littoral}}
{{wiktionary|circumlittoral|infralittoral|sublittoral|supralittoral}}

In [[oceanography]] and [[marine biology]], the idea of the littoral zone is extended roughly to the edge of the [[continental shelf]]. Starting from the shoreline, the littoral zone begins at the spray region just above the high tide mark. From here, it moves to the intertidal region between the high and low water marks, and then out as far as the edge of the [[continental shelf]]. These three subregions are called, in order, the [[#Supralittoral zone|supralittoral zone]], the [[#Eulittoral zone|eulittoral zone]], and the [[#Sublittoral zone|sublittoral zone]].

===Supralittoral zone===
{{main|Supralittoral zone}}

The ''supralittoral zone'' (also called the ''splash'', ''spray'' or ''supratidal zone'') is the area above the spring high tide line that is regularly splashed, but not submerged by ocean water. Seawater penetrates these elevated areas only during storms with high tides. Organisms that live here must cope with exposure to fresh water from rain, cold, heat, dryness and [[predation]] by land animals and seabirds. At the top of this area, patches of dark [[lichen]]s can appear as crusts on rocks. Some types of [[Common periwinkle|periwinkles]], [[Neritidae]] and detritus feeding [[Isopod]]a commonly inhabit the lower supralittoral.<ref name="Yip and Madl">Yip and Madl</ref>

===Eulittoral zone===
{{See also|Intertidal zone}}

The ''eulittoral zone'' (also called the ''midlittoral'' or ''mediolittoral zone'') is the ''intertidal zone'', known also as the ''foreshore''. It extends from the spring high tide line, which is rarely inundated, to the spring low tide line, which is rarely not inundated. It is alternately exposed and submerged once or twice daily. Organisms living here must be able to withstand the varying conditions of temperature, light, and salinity. Despite this, [[Productivity (ecology)|productivity]] is high in this zone. The wave action and turbulence of recurring tides shape and reform cliffs, gaps and caves, offering a huge range of habitats for sedentary organisms. Protected rocky shorelines usually show a narrow, almost homogenous, eulittoral strip, often marked by the presence of [[barnacle]]s. Exposed sites show a wider extension and are often divided into further zones. For more on this, see [[intertidal ecology]].

===Sublittoral zone===
{{See also|Neritic zone}}

The ''sublittoral zone'' starts immediately below the eulittoral zone. This zone is permanently covered with seawater and is approximately equivalent to the [[neritic zone]].

In [[physical oceanography]], the sublittoral zone refers to coastal regions with significant tidal flows and energy dissipation, including non-linear flows, [[internal wave]]s, river outflows and oceanic fronts. In practice, this typically extends to the edge of the [[continental shelf]], with depths around 200 meters.

In marine biology, the sublittoral zone refers to the areas where sunlight reaches the ocean floor, that is, where the water is never so deep as to take it out of the [[photic zone]]. This results in high [[primary production]] and makes the sublittoral zone the location of the majority of sea life. As in physical oceanography, this zone typically extends to the edge of the [[continental shelf]]. The benthic zone in the sublittoral is much more stable than in the intertidal zone; temperature, water pressure, and the amount of sunlight remain fairly constant. Sublittoral corals do not have to deal with as much change as intertidal corals. [[Coral]]s can live in both zones, but they are more common in the sublittoral zone.

Within the sublittoral, marine biologists also identify the following:
*The '''infralittoral zone''' is the algal dominated zone, which may extend to five metres below the low water mark.
*The '''circalittoral zone''' is the region beyond the infralittoral, that is, below the algal zone and dominated by [[Sessility (zoology)|sessile]] animals such as [[mussel]]s and [[oyster]]s.

Shallower regions of the sublittoral zone, extending not far from the shore, are sometimes referred to as the '''subtidal zone'''.