THE INTERNAL ZONE

2 Pages 613 Words

The Intertidal Zone
Littoral Zone Animal Printouts
The intertidal area (also called the littoral zone) is where the land and sea meet, between the high and low tide zones. This complex marine ecosystem is found along coastlines worldwide. It is rich in nutrients and oxygen and is home to a variety of organisms.



An Inhospitable, Changing Environment:
Much of this inhospitable environment is washed by the tides each day, so organisms that live here are adapted to huge daily changes in moisture, temperature, turbulence (from the water), and salinity.
· Moisture: The littoral zone is covered with salt water at high tides, and it is exposed to the air at low tides; the height of the tide exposes more or less land to this daily tide cycle. Organisms must be adapted to both very wet and very dry conditions.
· Water Movement:The turbulence of the water is another reason that this area can be very difficult one in which to survive - the rough waves can dislodge or carry away poorly-adapted organisms. Many intertidal animals burrow into the sand (like clams), live under rocks, or attach themselves to rocks (like barnacles and mussels).
· Temperature: The temperature ranges from the moderate temperature of the water to air temperatures that vary from below freezing to scorching.
· Salinity: Depressions on the shores sometimes form tide pools, areas that remain wet, although they are not long-lasting features. The salinity of tidepools varies from the salinity of the sea to much less salty, when rainwater or runoff dilutes it. Animals must adapt their systems to these variations. Some fish, like sculpin and blennies, live in tide pools.
Vertical Zones:
The littoral zone is divided into vertical zones. The zones that are often used are the spray zone, high tide zone, middle tide zone, and low tide zone. Below these is the sub-tide zone, which is always underwater.
· Spray Zone: Also called the Upper Littoral, the Supra...