Rocky Intertidal Zone

1
Rocky Intertidal Zone
2
General Characteristics

• Steep coasts without large amounts of sediment
• West coast of US
• Active margin
• Uplift
• Northeast Coast of US Canada
• Ice sheets scraped sediment from the shelf

3
Conditions

• Plenty of food
• Shallow water lots of light
• Nutrients
• Detritus
• Brought in by waves tides
• Most important food source in many communities

4
Organisms in Rocky Intertidal

• Mainly epifauna
• Adaptations for attachment
• Byssal threads
• Holdfasts
• Tube feet
• Cement

5
Barnacles
6
Periwinkles
7
Sea Star
8
Sea Anemones
Lobsters
Mussels
Sea Urchin
9
Palm Seaweed
10
Rocky Coast Communities

• West coast of US has more mature communities
• Less seasonal changes
• Main limiting factor is predation
• East coast is less mature
• Seasonal population changes
• Main limiting factor is climate

11
Competition for Space

• Sessile organisms need place to attach
• Space is limited
• Ways to outcompete other species
• Large larva
• Loosen competition from rock
• Grow over competitors

12
Ecological Succession
13
Vertical Zonation

• In rocky intertidal, species not found
  throughout rather in a particular range
• Distinct bands of organisms at characteristic
  height in intertidal
• Upper limit usu. determined by physical factors
• Lower limit determined by biological factors
  predation, competition

14
(No Transcript)
15
(No Transcript)
16
Keystone Predator
17

• STARFISH FEEDING ON MUSSEL BED