Other animals like crabs and sea stars aren't as common in this area because it gets so little sea water. The next area is the high-tide zone or the upper midlittoral zone . It is exposed to some water during high tide when waves wash over it. Organisms that live in this zone must be able to survive in both wet and dry environments. Tidepools often form in this region when water is trapped in depressions in rocks and the sand.
Some animals live in tidepools for their whole life, others wash in and out with the tides.
Organisms that live in tide pools have to adjust to changes in water temperature, and salt and oxygen levels during the course of a day. Half and Half The mid tide zone or the lower midlittoral zone is completely covered and uncovered twice a day by the tides. Plants and animals in this zone must be able to live in air and water. Animals like mussels and anemones hold in moisture by closing up when the tide goes out. Seaweeds that grow here can hold onto their moisture until the tide returns.