Intertidal zone

area between tide marks

Intertidal zones are coastal areas, the space between high and low tides. They often have rock, sand or mud that is under water at high tide, and above water at low tide.

Starfish, sea urchins and mussel shells in a rocky intertidal zone

Rock pools are common on some shores. These areas are often home to many species of crabs, shellfish, shallow water fish and many other animals. Many environmental things affect these areas, for example, waves, sunlight, salinity, wind, and water tide. About 300,000 species have been found in the intertidal zone. These species have to tolerate the pounding of waves, the changes in temperature, and the drying out at low tide.

Panoramic view of tide pools in Santa Cruz, California from spray/splash zone to low tide zone