A tide pool or rock pool is a shallow pool of seawater that forms on the rocky intertidal shore. These pools typically range from a few inches to a few feet deep and a few feet across. Many of these pools exist as separate bodies of water only at low tide, as seawater gets trapped when the tide recedes. Tides are caused by the gravitational pull of the sun and moon. A tidal cycle is usually about 25 hours and consists of one or two high tides and two low tides.
The site of a tide pool in Santa Cruz, California showing sea stars, sea anemones, and sea sponges.
A tide pool in Porto Covo, west coast of Portugal
Tide pools in Santa Cruz, California from spray/splash zone to low tide zone
Low tide zone in a tide pool
The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide: in other words, the part of the littoral zone within the tidal range. This area can include several types of habitats with various species of life, such as seastars, sea urchins, and many species of coral with regional differences in biodiversity. Sometimes it is referred to as the littoral zone or seashore, although those can be defined as a wider region.
Tide pools at Pillar Point showing zonation on the edge of the rock ledge
A rock, seen at low tide, exhibiting typical intertidal zonation, Kalaloch, Washington, western United States.
A California tide pool in the low tide zone
Nutrition (Eutrophic) Pollution in Assateague Island National Seashore, Maryland