The Intertidal Zone

By Sheede & Kim K.

The intertidal zone is one of the many biomes on the earth. Each biome has its own organisms and climates. The biome we will focus on is the intertidal zone. The intertidal zone is located at a the shore line of a beach. What is the intertidal zone? It is the area of water between low and high tide. Part of the day it is in the sunlight and air. The other part it is covered with salt water. It is basically where the land meets the ocean.

We are going to focus on the intertidal zone of New England. The climate in New England is a mild spring and fall, a cold winter that is usually harsh, and a very humid summer. In fall the leaves change colors and it can become chilly. During the summer it can become pretty hot. The water stays cold all year- round. In the summer it may become a little warmer, but overall it is cold. For one example of water temperature, during late spring and early summer, the temperature is usually between 30 to 50 degrees Fahrenheit.

This is a picture of the Laurencia seaweed sample found in Hawaii.

When looking at the intertidal zone of New England one can see things like barnacles, snails, and shells. There are many types of organisms located at the intertidal zone. Many of these organisms are classified in kingdom Protista. Protista include organisms like seaweed and plankton. An example of red green seaweed is Laurencia pinnatifida. It is a faded purple color and is found on the Atlantic coast. Another seawood is the Dasya elegans. It is a pink or red color, and it is found on the Cape Cod shore. Asperococcus echinatusis is found along the New England coast. It is olive in color and grows in clusters. Arthrocladia villosa is a very rare organism that is usually found on the New England coast. Callithamnion pylaisoei is found in the northern Boston coast. Microclaudia borealis is dark brown and located on northern Atlantic coast. Spyridia flamentosa is purplish - red color and is found on the beaches from Cape Cod. These are examples of seaweed found on the New England coast line.

The following are examples of some of the invertebrates found in the intertidal zone. The sponge Grantia ciliata is in phylum Porifera which includes all sponges. The organism Aurelia havidula is an example from the phylum Cnidaria which is a jellyfish. One example of phylum Mollusca is the snail Lottia gigantea.

This is a picture of a basic horseshoe crab, or Limulus makauccanus.

The following are some examples of the vertebrates found in the intertidal zone. The class Crustacea include the horseshoe crab, Limulus moluccanus. The organism Mysis sternolepis is found in the subclass Malacostraca which includes some types of fish.

Adaptation is important to an organism's survival. Laurencia pinnatifida is characterized as red sea weed. This algae has a flat surface and is thick. The branches are very thin so that water can easily pass through it. This prevents this algae from too much pressure against it. It also attaches to rocks. This allows it to not wash onto the shore.

Dasya elegans is pink or red. It has thread like branches. This allows water to easily pass through it, so the algae can respire more.

Aurelia flavidula is about six inches in diameter. This jellyfish can easily flow through the water. It can sting its enemies allowing it to live longer. The Lottia gigantea is a type of horseshoe crab. It can easily move along the bottom of the water. It has a shell to protect itself from enemies. These organisms are adapted to their environment.

Pollution can be a threat to the intertidal zone. People litter the beach shores. Once water has become polluted it becomes much harder to live.

Some other problems are humans collecting creatures by killing them. For example people dry up starfish and seashells for decorations. This can be a threat.

Symbiosis exists between some organisms of the intertidal zone. For example, snails attach themselves to seaweed, so they do not get washed up on shore. The seaweed attaches itself to rocks which are non- living. This is an example of commensalism, where one organism is benefited and the other organism is unaffected.

This shows the environment of the intertidal zone.



Arnold Augusta. The Sea- Beach at Ebb- Tide. 1968. Pan American


Kenneth Gosner. Atlantic Seashore. 1978. Library of Congress


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