Littoral zone

Author: Leandro Alegsa

13-11-2022

The littoral zone refers to that part of a sea, lake or river which is close to the shore. In coastal environments the littoral zone extends from the high water mark, which is rarely under water, to shoreline areas that are permanently submerged. It always includes this intertidal zone and is often used to mean the same as the intertidal zone. However, the meaning of "littoral zone" can extend well beyond the intertidal zone.

In oceanography and marine biology, the idea of the littoral zone is extended roughly to the edge of the continental shelf.

Lakefront zoning

The majority of photosynthetic activity takes place in the sunlit littoral. The animals settled in this habitat form spatially delimited organizational groups. In the littoral of a lake, there are three plant zones: Reed zone, floating leaf zone, and diving leaf zone.

Epilitoral, alder belt, willow scrub zone

Moisture-tolerant plants thrive on the lakeshore, hygrophytes such as mosses, rushes and marsh marigold. Alder swamp forests with willow, downy birch and black alder determine the picture among the plants of the higher floors.

Supralittoral, splash zone

This strip of shore is not reached by the waves. However, it is soaked by the splash water of the waves breaking on the shore. A rinsing seam can form here.

Eulittoral, surf zone

Strong mechanical forces prevail in the surf zone, which do not allow larger plants to grow. However, firmly attached, oxygen-loving organisms such as strudel worms (Turbellaria spec. ) and crust-forming cyanobacteria can settle here.

Infralittoral or sublittoral

This zone is home to larger plants that are adapted to a constantly flooded soil. They have an aerenchyma, an interconnected system of large intercellular spaces, so that the roots can also be supplied with oxygen. This riparian area serves as a spawning and breeding ground for many fish, amphibians, birds, and insects. The infralittoral is divided into different sections.

Below the shore zone, separated by the trophic compensation layer, lies the dark depth region, the profundal.

Zoning of the sea coast

The zoning designation of the littoral on a seashore depends on the water depth and the presence of tidal influence (tide, tidal).

Epilitoral

In the vicinity of the coast, in the dune area behind beach walls and dikes, the influence of the sea can still be seen through rising saline groundwater and salt water dust in the air. At most, extreme storm surges reach this area.

Supralittoral or Supratidal

The splash zone above the high tide line outside the tidal range, which is only briefly covered by water during storm surge events.

Eulittoral, hydrolittoral, littoral or intertidal

The intertidal zone between the high and low tide lines, characterized by the alternation between low and high tide. Tide pools are found here with rocky substrates. Species-rich mangrove forests also form on tropical coasts.

Sublittal or Subtidal

The shallow (neritic) shelf region permanently covered by water, below the low-water line to the shelf edge at an average depth of 200 m. Coral reefs also form near the shore, initially as fringing reefs, and on islands also coral atolls.

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