Upload
anthony-austin
View
217
Download
0
Embed Size (px)
Citation preview
Intertidal Glory
Christen Foehring
11/12/09
Area of the shore between mean high water and mean low water Also known as the littoral zone
What is intertidal zonation?
• Banding of organisms in the intertidal zone
• Zones are not absolute• Sorted out by ability to
cope with stresses• Also called vertical
zonation
Pacific Northwest Rocky Intertidal Zones
A Dynamic Environment
• Temperature
• Light
• Moisture/Desiccation
• Wave Shock/Energy
• Dissolved Oxygen
• Food Supply
Rocky shores
• Zonation of rocky shores:– Splash/ Spray zone (rarely covered by water)– Upper intertidal zone– Middle intertidal zone– Lower intertidal zone (rarely exposed)
• Upper zones have mostly shelled organisms• Lower zones have many soft-bodied
organisms and algae
Rocky shores: Intertidal zonation and organisms
Different Stresses for Different Zones
Upper Zones• Exposure (air &
weather)• Heat• Predation by birds
and land animals• Wave turbulence
Lower Zones• Competition (food &
space)• Predation by aquatic
animals
General Rule of Thumb…
• Its lower limit is determined by biological factors (i.e. predation, competition)
• The lower an organism goes, the more capable it must be of withstanding competition pressures for space and resources and avoiding predation.
• An organism’s upper limit is determined by physical factors (i.e.desiccation,temperature).
• The higher an organism lives, the more capable it must be of tolerating exposure to air and sun.
Splash Zone
• Above high-tide level
• Seldom submerged• High air exposure
Splash Zone
• Periwinkles dominate
• Limpets• Lichens• Encrusting algae• Shore crabs
http://www.elkhornslough.org
http://2.bp.blogspot.com
Pickleweed a.k.a
Sea Asparagus
Upper Intertidal Zone
• Submerged regularly (once or twice a day)
• Affected by desiccation, competition, & predation
Upper Intertidal Zone
Barnacles dominate
Photo Credit: Trina (Fish 351)
Middle Intertidal Zone
• Lower limit of barnacles is set by competition with mussels in this zone
• Mussels are more prone to drying out than barnacles
• Lower limit of mussels is set by seastars
Middle Intertidal Zone
• Mussels
• Barnacles
• Seaweeds
Keystone Species:Pisaster !
• Voracious predators• How do seastars ingest
their prey?• Often found in
middle/lower intertidal (prone to drying out)
• What happens when humans remove the seastars?
Lower Intertidal Zone
• Submerged most of the time
• Good place for predators and seaweeds
• Compete for light & space
Lower Intertidal Zone
• Seaweed• Surfgrass• Anemones• Seastars
• Green Algae– Absorb short & long
wavelengths– Ex. Sea lettuce (Ulva spp.)
• Brown Algae– Capable of absorbing
shorter wavelengths– Ex. Rockweed (Fucus
gardneri)
• Red Algae– Absorb short blue-green
light – Ex. Encrusting coralline
algae (Lithothamnion spp.)
http://lh4.ggpht.com
http://plantphys.info
Which zone? How can you tell?
What determines the limits of these species’ intertidal
ranges?
What would happen if you removed the seastars from
this tidepool?
• Mini Quadrats• Piling Zonation aka
“personal piling”– Intertidal Zonation– Compare/Contrast
Species– Art
• Perspective writing (intertidal organism)
• Periwinkle Observation Activity
• Common PNW marine intertidal organisms– Answers to the questions kids ask most
often (what is it, what does it eat, who eats it, can I eat it, where does it live, is it like a ___?)
• Tidepool Explorations - boots & flashlights required!
Come see her at Benaroya HallWednesday, November 18,2009
7 PM - $25
http://www.sundancechannel.com/greenporno