The intertidal zone is a gradient that stretches between land and sea and one in which there is constant change as sea water moves with the tides, alternately submerging and exposing areas of the sea floor. For this reason, the environmental conditions and species compositions vary throughout the intertidal zone.
The intertidal zone can be subdivided into the high tide zone and the low tide zone. The high tide zone (also called the upper littoral) is the area of the intertidal zone located near the high tide mark is submerged only when the tide reaches its peak. Conversely, the area of the intertidal zone located near the low tide mark is exposed only when the tide reaches its lowest point. This portion of the intertidal zone is referred to as the low tide zone (or lower littoral).
Organisms that inhabit the different regions of the intertidal zone are exposed to water and air in differing proportions. Thus there is a gradient of species that forms along the transect of the intertidal zone.
- Ecozone: Marine
- Ecosystem: Intertidal Zone