The Intertidal Zone

The Intertidal Zone

The intertidal zone is the area of the sea floor that is uncovered and recovered by the tides. At high tide, the intertidal zone is submerged beneath sea water and at low tide it is exposed to air. There are two main types of intertidal zones that experience this daily change, the sandy shore and the rocky shore. Each has different characteristics and special organisms that survive there. These different species tend to inhabit different zones in which they can handle but there are many stresses that they are exposed to. Animals at low tide have to worry about being exposed to predators, desiccation, temperature change, wave shock, light amount, and salinity. The intertidal zone presents a harsh set of challenges to inhabiting organisms, who must adapt to constantly changing conditions. Three organisms that have learned to adapt are clams, nudibranchs, and limpets.

Clams have made many adaptations to protect themselves from the stressors of the intertidal zone. They had adapted to retain more water and be protected from predators. The clam’s muscles have become stronger overtime to be able to close its valves tighter. When this muscle closes its valves tightly it can preserve all water for long periods of time so that it does not dry out. The shell is also a great protection, its thick surface and strongly closed valves make it hard for predators to penetrate. Also, its neck is hidden inside its shell where it is out of reach of predators. The clam, including the Butter clam, has this amazing shell which is an adaption to counter the difficulties of the intertidal zone.

Another species that has adapted are the nudibranchs. A nudibrach has no shell, no spine, and can not move very fast. They seem to have no protection from predators but have adapted because the low tides have continued to expose them. Nudibranchs have developed their own protection. They are not cnidarians on their own but have found a way to steal nematocysts. Nudibranchs, like the shaggy mouse, have become immune to the anemone sting and when consuming an anemone they transfer the nematocyst to their own back. They now contain nematocyst on the tentacle like extensions off their backs and are able to produce a sting to catch prey or scare off predators. Also, nudibranchs