Intertidal Ecosystem
What does intertidal mean?
Between the tides
-Intertidal Ecosystems: land between the high
tide and low tide
What do all intertidal ecosystems have in common?
-Constantly changing environment
-Submerged part of the day
-Exposed part of the day
-Home to extremophiles
Two Major Types
-Rocky Intertidal
-Sandy Shores
Rocky Intertidal
Observe Rocky Intertidal
Key Characteristics of the Rocky Intertidal
Foundation: Bare rocks and/or rocks covered in algae
-At low tide, the rock is exposed leaving tidepools
Key Characteristics of the Rocky Intertidal
Tidepools: As the water ebbs to reach low tide, pools
of water are left behind in the crevices created by the
rocks
What environmental stressors do organisms of
the Rocky Intertidal?
◦Waves
◦Temperature changes
◦Salinity Changes
◦Air exposure
◦Dessication
◦Fully submerged
Sandy Shore Intertidal
Observe Sandy Shore Intertidal
Key Characteristics
Foundation:
- sand grains, crushed shells, smaller pebbles
◦Usually bordered by coastal grasses and plants
◦Reshaped Daily, how?
Sand
Can be classified by :
Grain size
Color
Composition
Morphology (angularity and shape)
Surface texture
It’s not all it appears to be
It’s not all it appears to be
Environmental Issues
Beach Combing
-Individuals or groups taking things of interest from the
beach
How can this have a negative impact on the environment?
Removal of Beach Wrack
Beach Wrack: Seaweed that is brought
in by the tides and left on the beach
-People will remove beach wrack
because it is not visually appealing
Why do you think removing beach
wrack can have a negative affect on the
environment?
Trespassing onto Sensitive Breeding Areas
Many endangered birds and turtles breed on the sandy
shore
-If people are not careful, they can trample and destroy
birds nests and turtles nest
Organisms of the Intertidal
Organisms of the Intertidal
Seaweed (kingdom Protista)
Class Bivalvia (phylum Mollusca)
Class Gastropoda (phylum Mollusca)
Class Crustacean (phylum Arthropoda)
Phylum Echinodermata
Phycology: The study of seaweed
Three different types of seaweed:
Phylum Ochrophyta
Phylum Rhodophyta
Phylum Chlorophyta
What commonality do you see in the names?
Phyta: plank like (photosynthesizers)
What differences do you see in the names?
Phycology: The study of seaweed
Three different types of seaweed:
Phylum Ochrophyta (Brown Seaweed, middle)
Phylum Rhodophyta (Red seaweed, deepest)
Phylum Chlorophyta (Green Seaweed, most shallow)
Thinking about light, why might you find green as the
shallowest and red as the deepest?
Phylum Chlorophyta (Green Seaweed)
-Chlorophyll makes them green
-Attach to rocks in the Rocky Intertidal
-Acts as a primary producer
Human Use of Green Algae
-Method of helping to cure cancer
-Biofilter
-Food
-Biodiesel
Gastropoda: What do you observe?
Gastropoda
-“stomach foot”
-Soft body usually surrounded by one shell
-Some have completely lost their shells (sea slugs)
Gastropoda Anatomy
If Shell is present
◦Torsion: shell and body is coiled
◦Operculum: Trap door that can seal the snail in its shell
Nudibranchs the Unshelled Gastropoda
-Nudi: Naked, Branch: Gills, Naked Gills
New Defenses:
-Ink
-Noxious Chemicals
-Swimming
-Strong Senses
Crustaceans
Crustaceans
-Exoskeleton and jointed appendages
Crustacean Growth
-Crustaceans grow but their
exoskeleton does not grow with them
Solution: Molting
◦ Peels back the carapace and crawls out of
the old exoskeleton
◦ Finds a place to hide while it hardens
◦ Shell hardens and Crustacean is mobile
again
Bivalvia: Clams, Scallops, Mussels, etc.
What do you observe?
Bivalvia
-Two Shells that encloses a soft body
-Shells are mirror image of each other (bilaterally
symmetrical)
-Usually (not always) sedentary
Mussel
Bivalve Anatomy
Gills: Used for
breathing and
feeding
Mantle:
Fleshy
body of the
mussel.
Adductor Muscle:
enables bivalves
to tightly shut
their shells
Foot
What do the rings mean?
Importance to Intertidal Communities?
Why might the second picture be more productive than the first picture?
What are the mussels doing to enhance the environment?
Importance to Intertidal Communities?
-Bivalves, especially Mussels, colonize and cover the rocks
◦ Providing food
◦ Provides texture for the rock meaning more space for
other organisms to live
How to tell of a Bivalve met its fateful
end
Moon Snail
Sea Otter
Crab
Sea Star
Invasive Species
-Species that are non-native to a specific
location
-Thrive in the new environment
◦Outcompete native species for food
◦No natural Predators
◦Can potentially destroy an environment
Freshwater Invasive Species
-clog pipes
-increase drag on boats
-sink buoys
Introduction:
Ship Ballast water
https://tpwd.texas.gov/education/hunter-education/onlinecourse/wildlife-conservation/invasive-aquatic-species
Echinodermata “Spiny Skin”
-Pentaradial Symmetry
-Hydrostatic skeleton for movement
-Can sense light and dark
-have the ability to regenerate
Major Groups of Echinoderms
-Sea Stars
-Sea Cucumbers
-Sand Dollars
-Sea Urchins
-Feather Stars
Sea Star Anatomy Coloring
https://s-media-cache-ak0.pinimg.com/originals/a3/05/13/a305137f511090e593a09694d11edac0.jpg
Overarching Question
Should we restrict people’s access to intertidal
ecosystems to keep biodiversity?
Case Studies
Human Impact on Intertidal Zones
Tourism