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# What is the intertidal zone?

## The **intertidal zone** is the area where the **ocean meets the land** between high and low tides.

A tide pool within Monterey Bay National Marine Sanctuary.

Intertidal zones exist anywhere the ocean meets the land, from steep, rocky ledges to long,			sloping sandy beaches and mudflats that can extend for hundreds of meters. Four physical			divisions, each with distinct characteristics and ecological differences, divide the intertidal zone.			They are the:

            - Spray zone:  dampened by ocean spray and high waves and is submerged only						during very high  tides  or severe storms.
            - High intertidal zone:  floods during the peaks of daily high tides but remains dry for					long stretches between high tides. It is inhabited by hardy sea life that can withstand					pounding waves, such as  barnacles , marine snails,  mussels ,  limpets ,  shore crabs , and					 hermit crabs .
            - Middle intertidal zone:  over which the tides ebb and flow twice a day, and which is					inhabited by a greater variety of both plants and animals, including  sea stars  and anemones.
            - Low intertidal zone:  virtually always underwater except during the lowest of					 spring tides . Life is more abundant there because of the protection provided by the water.

Sea creatures arrange themselves vertically in the intertidal zone depending on their abilities to			compete for space, avoid predators from above and below, and resist drying out. Residents of the			higher intertidal zones can either close themselves up in their shells to remain moist and ward off			predators, or are mobile enough to retreat to a submerged zone when the tide goes out. In the			lower parts of the intertidal zone, many plants and animals attach themselves in place and are			very sturdy, very flexible, or otherwise well suited to stand up to wave energy.

Larger marine life, such as seals, sea lions, and fish, find foraging for food ideal at high tide in			the intertidal zone, while a large variety of shorebirds, looking for their meals, stroll hungrily			over the intertidal zone at low tide.

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Take only photographs and leave only footprints! Empty shells are recycled and reused by		animals such as hermit crabs. Seaweed tossed on the shore decomposes and recycles nutrients		back into the marine ecosystem.

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**Last updated:**   01/20/23**Author:** NOAAHow to cite this article

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