Intertidal Zone

Ms. Bridgeland

Intertidal Zone• Shallow area connected to the beach that is made up of

high tides and low tides

• Talk about habitats that exist on ROCKY shores

• Animals that live in the intertidal zone endure harsh conditions because of the waves that bring the high and low tides.

** Crashing waves engulfing them at times

– At other times, sun beats down and no water is reaching them

Rocky Shores

• Rocky Shores are found along much of both coasts of the United States – Ex. California coast

Intertidal Zones

• Highest rocks on highest high tide line make up the spray zone

–A strip of algae makes up the highest high tide line

Intertidal Zone

• Organisms that live in the intertidal zone must be able to tolerate the pounding waves

• Changes in salinity and temperature

• Have to withstand periods of being underwater and periods of being exposed to air

Adaptations for animals in the Intertidal Zone

• Most avoid drying out

• Hide from predators

• Find food in a harsh setting

Intertidal Zone• Spray Zone = the highest rocks above the high-

tide line ---a strip of algae shows the highest high-tide line

• Rocks below the spray zone are covered in barnacles. These rocks are also home to limpets (flat animals with large, muscular feet that allow them to hold tightly to rocks)

• They release drops of mucus around the edges of their shells

• Mucus form a tight seal

Rocks below the spray zone have barnacles:

Barnacles

• Can close up their hard shells –this action traps a drop of water inside to carry the barnacles through the dry period until the next high tide

Rocks below the spray zone also have LIMPETS:

Limpet

Tide Pools

What are Tide Pools? • They are “pools” of water that are left when a tide

comes in because the land on the beach is uneven and has crevices and depressions

• When the tide goes out, water remains in depressions among the rocks

• What happens when water in a tide pool evaporates?

• What happens when it rains on water in a tide pool?

Animals in a Tide Pool

• Sea urchins: crawl slowly along the bottom of the tide pool and uses its spine to dig a hole in the bottom of the tide pool to protect itself while it waits for food.

• Sea anemones: wait under shady rock ledges and wait for the incoming tide to bring a fresh supply of plankton and other food particles

– Some sea anemones can survive without water for 2 weeks

• Sea Stars: cling to the rocks with rows of tiny suction cups

Sea Urchin

Sea Anemone

Sea Stars

Estuaries

• Another important environment along the ocean’s edge

• Coastal inlets or bays where fresh water from the river mixes with salty ocean water

Coastal Inlet: The “entrance” or connection between a bay and an ocean

Bay: a large body of water connected to the ocean or sea

Fresh water and Salt water mix

“Brackish”

• Water that is partly salty and partly fresh water

• Water that is in an estuary is called brackish.

• Fresh water + Salt water = Brackish.

Coastal Wetlands

• Are found in and around estuaries.

• Coastal wetlands have brackish, so have salt and fresh water mixed together

• Wetland: a land area that is saturated (or completely filled) with water

• In the United States, most wetlands are: – 1) Mangrove Forests– 2) Salt Marshes

Coastal Wetland

1) Mangrove Forest

• A wetland that is made up of Mangrove trees that grow in brackish water

• Mangrove trees protect the coastline from the wind and waves during storms

• Mangrove trees’ roots trap sediment from the land and create a protected “nursery” rich in nutrients for many young animals

• Orchids, reptiles, birds, crabs

Mangrove Forest

2) Salt Marshes

• Have smelly mud made up of sediments, animal and plant matter, and nutrients carried into the marsh by fresh water and tides

• Cordgrass is the most common plant in the marsh –survives well in salt water

• Animals that live in salt marshes: fish, crabs, shrimp, oysters, crabs, herons, egrets, stilts

Salt Marshes

Where are Mangrove Forests and Salt Marshes?

• Mangrove Forests are found in southern Florida and along the coast of the Gulf of Mexico

• Salt Marshes are found along the east coast from Massachusetts to Florida.