Intertidal Zones
Splash Zone
High Tide Zone
Mid Tide Zone
Pool
Low Tide Zone
Pool
Sub Tide Zone
The Splash Zone is the highest and driest of the intertidal zones. This uppermost region of the tidepool is seldom
covered by the ocean. Instead, it gets moisture from wave splash and rain. During high tide, crashing waves send
salty mist onto the splash zone. As a result, an interesting mix of plants and animals survive here Animals that
can tolerate the most dry conditions live here. Land-based (or terrestrial) animals and plants survive here if they
can tolerate some sea water. Marine animals and plants survive if they can tolerate exposure to air. As a result,
relatively few tidal animals live in this zone. Those terrestrial plants that can tolerate some salt water are found
here. Some organisms scavenge in the splash zone for fragments of plants and animals.
The High Tide Zone is underwater only during the highest tides. It is exposed to rough waves during high tide
and the hot sun during low tide. Organisms (plants and animals) that live here need to be able survive the strong,
rough waves, long periods of time out of the water, and long exposure to air in order to do well in this zone. The
High Tide Zone is a harsh environment for plants and animals to live in. Many of the animals that live in the high
tide zone have hard, flat shells to disperse the impact of the waves. When the tide is in, they busily move around
searching for food. When the tide is out, they must protect themselves from drying out. All of the high zone
animals have incredible abilities to stay attached to the rocks as the waves crash down. They also need certain
resources to live here like food and shelter. The rocks in these tide pools make a good shelter.
The Mid Tide Zone is 50% underwater, covered and uncovered by the tides twice a day. Animals have adapted
to the changing conditions in this zone by learning to conserve their water until the high tide covers them
again. The Mid Tide Zone is the most active intertidal zone of them all because it is fully covered and uncovered
each day, so many animals cross over and feed in this region as the tides change. While the Mid Tide Zone is
covered and uncovered twice a day, the high and the low intertidal zones are not. Animals in this zone have
adapted to being immersed in air and in sea water. Some of the animals that live in this zone eat tiny particles
of food from the tidewater.
The Low Tide Zone is usually covered by water and is exposed to the air during only unusually low tides. In other
words, this zone is mostly covered by water at almost all times. The creatures who make this zone home are less
tolerant of being exposed to the air. The low zone receives the most consistent amount of water. In fact, this intertidal zone gets 90% water, and only 10% pure sunshine. Only during the lowest tides is this area exposed to
air. As a result, compared to other regions of the tidepools, low zone animals need the most water and cannot be
in the sun for too long. Because of the longer submersion period, organisms here do not have to be as sturdy and
adaptive. That is why you can find many intertidal plants and animals living in the Low Tide Zone.
The Sub Tide Zone is rarely exposed to the air. Some of the most exciting and delicate animals live in this area.
Only on the very lowest tides of the year can you access the creatures here. This area is submerged most of the
time, exposed briefly during extreme low tides. The Sub Tide Zone is a fairly diverse soft-bottom habitat, home to
a wide range of organisms. This zone provides habitat to a large diversity of marine plants and animals in contrast
to the other zones. Animals of the Sub Tide Zone often prey upon the animals in the Low Tide Zone. The Sub Tide
Zone is hard to access because it is rarely exposed to the air, making it good shelter. However, the organisms here
are more fragile in general and cannot tolerate much exposure to the air or sun.