Title: Marine Communities of San Salvador
1Marine Communities of San Salvador
- Intertidal - Hardbottom
- White zone Supralittoral zone
- Gray zone
- Black zone
- Yellow zone
- Intertidal - Softbottom
2The Intertidal Sits Between the Supralittoral and
the Subtidal Zones
Supralittoral
Subtidal
3Physical/Chemical Factors
- Temperature
- Wave shock
- Tides
- Impact of Slope
- Low tides ? physiological stress
- High tides ? marine conditions are restored
- Light intensity
- Evaporation
- ph
4An Example Of How Exposure To The Sun Effects
Snail Shell Design
5How Design And Color Of A Snails Shell
Dissipates/Absorbs Heat
6What adaptations do you see in this tropical
nerite that help it lose heat?
7These mussels retain moisture by being densely
packed.
8Physical/Chemical Factors
- Temperature
- Wave shock
- Tides
- Impact of Slope
- Low tides ? physiological stress
- High tides ? marine conditions are restored
- Light intensity
- Evaporation
- ph
9Animals Are Subjected to Wave Shock Continuously
at High Tide
10- Adaptations to Wave Shock - Growth Forms Of The
Giant Green Sea Anemone
In sheltered areas
In areas with heavy wave action
11- Adaptations to Wave Shock
- Mussels at Intermediate Population Size Are Best
Adapted
Low
Intermed.
High
Large specimens washed away
Clumps ripped away
Waves dissipated and eddies form
12Physical/Chemical Factors
- Temperature
- Wave shock
- Tides
- Impact of Slope
- Low tides ? physiological stress
- High tides ? marine conditions are restored
- Light intensity
- Evaporation
- ph
13Types of Adaptations
- Attachment
- Bore into substrate (chitons and urchins)
- Byssal threads (molluscs)
- Feeding
- Prevention of dessication
14Boring By Sea Urchins
15Most organisms in rocky intertidal zones live
attached to rocks
16Attachment by Byssal Threads
17Two Types of Barnacles
18Barnacles Feed Using Appendages on Incoming Tides
19Intense Competition by Barnacles for Attachment
Sites
southeast Alaska
20Hardbottom Intertidal Food Webs
- Several different types of producers
- Detritus plays a central role
- Importance of drift into and out of the community
- Plankton are significant, too, as they arrive on
every wave
21Predation by a dog whelk (snail) on rock barnacles
22Hard Bottom Intertidal Community Food Web
23Intertidal ZoneCharacterized by Two Ecological
Factors
24The Intertidal Zone Is Characterized By Two
Ecological Attributes
- Zonation of Species moisture and temperature
gradients are established that influence species
distribution - Intraspecific and Interspecific competition for
attachment to substrate
We will study this while on San Salvador
25Vertical Zonation in Hardbottom Intertidal
Communities In Temperate Waters Along the Pacific
and Atlantic Coasts
26Pacific Coast
Atlantic Coast
27Vertical Zonation In Hardbottom Intertidal
Communities
- The upper limit of an organisms dispersion
pattern is typically set by physical factors such
as evaporation or dehydration. - The lower limit is generally set by biological
factors such as competition or predation.
Lets see how these factors interplay to
influence the dispersion patterns of two species
of barnacles
28Why Two Species of Barnacles Live Where They Do
Substantiated by removal studies
29Slope Gradient of Intertidal Zones Effects
Zonation
w
g
b
w
y
g
b
y
white, gray , black, yellow
30Zonation of a Rocky Shore
Gradual Slope
Steep Slope
31Gradual vs. Steep Rocky Shores(Hawaii)
32Vertical zonation as evidenced by bands of colors
33Vertical Zones in Tropical Hardbottom Intertidal
Communities
- White largely bleached out and wetted only by
storm-spring tides (Supralittoral) - Gray lower margin receives some immersion
- Black completely wetted during spring tides and
some high tides - Yellow the true intertidal zone
34Intertidal Zonation at North Point, San Salvador
White Gray Black Yellow
Subtidal
35A different view
36Here, the color zones appear to be reversed. I
dont know why.
37How Intertidal Communities are Experimentally
Studied
- Transplantation experiments several barnacle
studies - Removal studies barnacles limpet studies and
their grazing abilities - Caging/barrier experiments spiny lobsters
38What are the effects of spiny lobsters in the
rocky intertidal zone?
39Muscles dominate closed-end cages that exclude
spiny lobsters.
Cage removed to take photo
40Examples of Common Biological Activities Observed
in Rocky Intertidal Zones
- Biological succession
- Keystone species and predation
- Home ranges and homing behavior
- Symbiosis
- Competition
- Food
- Attachment sites
41How Succession Effects Community Structure in
Tide Pools
42Ecological Succession In A Mussel Bed
43How Keystone Species Impact the Structure of a
Tide Pool Community
44- Intertidal Tide Pools
- Effect of Removal of a Keystone Species on
Community Structure
45Homing Behavior in Limpets
46In what ways does this giant green sea anemone
receive nutrition?
47Vertical Zonation Can Extend into Subtidal
Communities
48End