What is Intertidal Zonation?
Intertidal zonation refers to the tendency of plants and animals to form visible communities along the marine shoreline, between the high and low tide lines. The ability of plants and animals to tolerate the special conditions of the intertidal zone determines where on the shoreline they can live. They must be able to survive pounding surf, daily flooding with salt water, exposure to the air, large fluctuations in temperature, and sometimes exposure to fresh water from the rain and seeping groundwater. Starvation is also a risk when the tide is out, since most intertidal animals feed only when they are submerged. The length of time that organisms are exposed to the air depends on the local tidal range and on where on the shore they are located. Close to the high tide line, plants and animals may be submerged only for an hour or two per day, and must be able to withstand prolonged drying. Near the low tide line, in contrast, they are almost constantly submerged. Different species have e
