Intertidal Zone

Intertidal
Zone
Intertidal Zone
• The area between high
and low tides
• Areas of the intertidal
may be above the
waterline or reach depths
of 10m
• Includes most other
coastal ecosystems
– Estuaries, beaches
Shore Types:
1. Rocky
•
•
•
Erosion
Sediments are removed quickly
Organisms must be adapted to hold onto
rocks
2. Soft/Sandy
•
•
•
Sediments are deposited
Helps prevent further land erosion
Unstable living envirionment
• Sand is continuously shifting
Tidal Zones
• Upper Intertidal
– supralittoral
• Middle Intertidal
– littoral
• Lower intertidal
– sublittoral
• Subtidal
– Outer sublittoral
The Supralittoral Zone
• Only submerged at highest tides
• “Splash zone” = only gets water
splashed on rocks
• Organisms must be adapted to
being exposed to air
– Adaptations to retain moisture
– Get oxygen from air or store
enough to survive until covered
again
– Resistant to high salt levels
• Examples: Lichens, algae, limpets
Littoral Zone
• Between high & low tide
– Submerged at high tide
– Exposed at low tide
• Tide pools
• Challenges = heat stress, drying
out, & water motion
• High Productivity leads to
competition
• Examples: Barnacles, sea stars,
mussels, sea urchins, brittle stars,
anemones, fish, crabs, seaweeds,
etc
The Sublittoral Zone
• Lower Intertidal
• Submerged most of the time
– Only exposed at the lowest tides
• Highly productive area
– Water, nutrients, sunlight
• Challenges = competition & crashing waves
• Examples: Fish, urchins, seaweed, seagrass,
sea palms, worms, sea cucumbers, sea stars
Outer Sublittoral Zone
• Subtidal Zone
• Area between low tide & continental shelf
• Shallow waters up to 10 m depth
– Kelp forests
Kelp Forests
• Grow in nutrient-rich, cold water with a
rocky bottom
– Areas with coastal upwellings
– Primary production exceeds terrestrial forests
• Dominated by kelp species
– Giant kelp can grow up to 60 meters
• Other organisms include: sea urchins, sea
stars, clams, sea otters, sea lions
Maintaining Ecological Balance
• Organisms in a Kelp forest
are interdependent
– Sea urchins eat kelp holdfasts
– Sea otters eat sea urchins and
need the kelp to keep from
drifting away while sleeping
– Hunting of sea otters resulted
in damage to kelp forests
because sea urchins ate the
kelp faster than it could grow.
Video: Coastal Biomes
1. Seashore Environments (1)
2. Characteristics of seashore biomes (5)
3. Mangroves (1)
4. Sandy Beach Zones (4)
5. Rocky Shore Zones (4)
6. Salt Marshes (1)
7. Human Impact on Coastal Biomes (5)