Intertidal Zones: Study Notes from the DepEd Module
The intertidal zone is the area that is above water level at low tide and underwater at high tide. It is also known as the foreshore or seashore.
The different habitats found in intertidal zones include:
- Coral reefs
- Salt marshes
- Mud flats
- Rocky shores
- Mangrove forests
Coral reefs – provide shelter to thousands of fish
- Corals are animals that feed on plankton.
- The reefs protect the coast from strong waves and currents.
- Reefs serve as the sanctuary for young fishes.
- Organisms found in coral reefs:
- corals
- fish – different kinds
- jellyfish
- sea anemones
- sea stars
Salt marshes – filled with seawater during high tide and drained during low tide
- Organisms found in salt marshes:
- clams
- crabs
- mussels
- oysters
- shrimps
- snails
- Plants found in salt marshes:
- sea grasses
- other plants that are tolerant of saltwater
Mud flats or tidal flats – areas where mud from the seas or rivers is deposited
- Organisms found in mud flats:
- migratory birds
- clams
- crabs
- fish
- mollusks
- mussels
- sand dollars
- shellfish
- Algae, like sea lettuce, provide food for the herbivores in this area.
Rocky shores – areas where solid rocks are found
- Organisms found in rocky shores:
- barnacles
- brittle stars
- hermit crab
- limpets
- mollusks
- periwinkle
- plankton
- prawns
- sea stars
- shore crabs
- shrimp
Mangrove forests – areas filled with mangrove trees
- These trees have adapted to saltwater.
- They serve as the breeding grounds for different kinds of fish and shellfish.
The abiotic factors that affect the organisms in intertidal zones are similar to those in estuaries:
- waves
- salinity
- amount of sunlight
- temperature
- type of soil