intertidal zonation robert perry. copyrights: all rights reserved © robert perry [email protected]...
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INTERTIDALZONATION
Robert Perry
Copyrights:
All Rights Reserved© Robert Perry
All the images in this presentation are copyrighted and are protected under United States and international copyright laws. They are the exclusive property of Robert Perry unless otherwise noted. The images are used here by exclusive arrangement with UCLA as part of this presentation only. The photographs may not be downloaded, reproduced, copied, stored, used or altered in any way without the express written permission of Robert Perry (or other sources as indicated). No images are within the Public Domain. The purpose of this presentation is non-profit education. Any other unauthorized use of this show is a violation of copyright law.
PREVIEW OUTLINE:
A. THE INTERTIDAL ZONE & ZONATIONB. FACTORS CONTROLLING ZONATION 1. Tides
a. Activity cycles & inter-specific competitionb. Desiccationc. Temperatured. Terrestrial & atmospheric forces
2. Wavesa. Wave shockb. Increased submergence
3. Slope of the shore 4. Substrate type
a. Attachment of larvaeb. Porosity of substratec. Movement of substrate
THE INTERTIDAL ZONE:
HighTideLine
LowTideLine
THE INTERTIDAL ZONE
A zone of life between the high tide line andthe low tide line on any beach.
High tide lineHigh tide line
Low tide lineLow tide line
Illustration: Stephenson & Stephenson (1972)
Distinct bands of life consisting of separatecommunities of organisms distributed from the
high tide line to the low tide line.
INTERTIDAL ZONATIONINTERTIDAL ZONATION
(more ocean water= more ocean life)
Increase in abundanceand diversity of life
as you move seaward.
INTERTIDAL ZONATION
Illustration: Stephenson & Stephenson (1972)
High tide lineHigh tide line
Low tide lineLow tide line
Major environmental factors controlling intertidal zonation:
MAJORFACTORS 1. Tides
2. Waves
3. Slope of the shore
4. Substrate type
Among all of the factors that control intertidalzonation, one common point stands out:
Organisms differ in their ability to survive.There is a “normal curve” that represents the
range of tolerance of organisms to eachenvironmental factor.
very hightolerance
very lowtolerance
What are TIDES ?
Tides are the regular and predictable variations in sea level
...that are caused by the gravitationalpull of the Moon and the Sun.
MAJORFACTOR
1. TIDES
1. TIDES
MAJORFACTOR
Q. What type of tide do we have herein southern California ?
(Calendar courtesy ofTidelines, Inc)
A. mixed semidiurnal tide.
Two unequal HIGH tides, and
(Calendar courtesy ofTidelines, Inc)
Two unequal LOW tides a day.
Intertidal Total Exposure to AirZone Hours per Year-----------------------------------------------------------------------Zone 1 High Intertidal 7,200 - 8,760 Zone 2 Upper-Middle 3,200 - 7,200 Zone 3 Lower-Middle 400 - 3,200 Zone 4 Low Intertidal 0 - 400
Exposure to air causes bands orzones of life along the beach.
Data modified from Hedgepeth, Ricketts and Calvin (1968).
1. TIDES
MAJORFACTOR
MAJORFACTOR 1. TIDES
Southern California hard substrateindicator species for each zone:
Zone: Name: Species:1 Splash snails2 Upper-mid barnacles3 Low-middle mussels4 Low algae
MAJORFACTOR
1. TIDES
Intertidal Zonesat La Jolla, California
Stephenson & Stephenson (1972)
snails
barnacles
mussels
algae
Alternate exposure to air and watercaused by the TIDES
results in intertidal organisms occupyingspecific zones according to their rangeof tolerance to dryness, temperature,predation, feeding, respiration andreproduction. This pattern can be
observed world wide.
MAJORFACTOR
1. TIDES
SUB-FACTORS
a. Activity cycles & inter-specific competition
b. Desiccation
c. Temperature
d. Terrestrial & atmospheric forces
Sub-factors that are related to TIDES:
MAJORFACTOR
1. TIDES
Sub-factors that are related to TIDES:
a. Activity cycles & inter-specific competition
Most intertidal activities are carried out during HIGH TIDE periods.
(Life functions occur better under water).
MAJORFACTOR
1. TIDES
Sub-factors that are related to TIDES:
a. Activity cycles & inter-specific competition
Predators have a range oftolerance. Beyond this range
their prey survive.Example: distribution of mussels.
MAJORFACTOR
1. TIDES
Low tide lineLow tide line
High tide lineHigh tide line
Intertidalzonation ona pier piling
Snailzone
Barnaclezone
Musselzone
Algaezone
young, littlemussels
old, largemussels
Low tide lineLow tide line
High tide lineHigh tide line
range of Pisaster - determined by thetides - it cannotmove up fartheror it cannot getback down tothe water line
at low tide.
young, littlemussels - above
the range of Pisaster
old mussels - too large to be
eaten by Pisaster
Pisaster
Sub-factors that are related to TIDES:
b. Desiccation.
The term desiccation means to losevital body fluids and dry up due to
exposure to the atmosphere.
MAJORFACTOR
1. TIDES
Sub-factors that are related to TIDES:
b. Desiccation.
There is a range of tolerance todesiccation among intertidal
organisms. Those that lose fluids fast
live in lower zones.
MAJORFACTOR
1. TIDES
Barnacles, Barnacles, BalanusBalanus sp., can close up sp., can close uptight to prevent water loss. Thus theytight to prevent water loss. Thus theysurvive in the survive in the upper intertidal zones. intertidal zones.
Algae, and the sea star, Algae, and the sea star, PisasterPisaster sp., sp.,tend to dry out easily. Thus theytend to dry out easily. Thus they
survive in the survive in the low intertidal zones. intertidal zones.
The sea anemone, The sea anemone, AnthopleuraAnthopleura,,closes up tight and has bits ofcloses up tight and has bits of
rocks and shells glued to its body.rocks and shells glued to its body.It also lives in moist crevices in theIt also lives in moist crevices in the
low intertidal. intertidal.
Sub-factors that are related to TIDES:
c. Temperature.
One of the most significant features of the sea is its high heat capacity,
its resistance to temperature change.
MAJORFACTOR
1. TIDES
Sub-factors that are related to TIDES:c. Temperature.
During high tide periods, temperatures areuniform and stable. But during low tide
periods temperatures can fluctuate widely.
MAJORFACTOR
1. TIDES
Sub-factors that are related to TIDES:
c. Temperature.
There is a range of tolerance totemperature among intertidal
organisms.Organisms with a wide range of temperature
tolerance tend to live in upper zones.
MAJORFACTOR
1. TIDES
HIGH TIDEOrganisms coveredby water of uniform
and stable temperature.
LOW TIDEOrganisms exposedto extreme ranges of
dry air, sun, wind,etc.
Sub-factors that are related to TIDES:
d. Terrestrial & atmospheric forces.
There is a range of tolerance toTerrestrial & atmospheric forces among
intertidal organisms.
MAJORFACTOR
1. TIDES
Sub-factors that are related to TIDES:d. Terrestrial & atmospheric forces.
Exposure at LOW tide to such forcesas hot sun, snow, wind, rain, as well
as surviving terrestrial predators such asracoons, crows, coyotes and humans may
effect the distribution of organisms.
MAJORFACTOR
1. TIDES
SUB-FACTORS
a. Activity cycles & inter-specific competition
b. Desiccation
c. Temperature
d. Terrestrial & atmospheric forces
Sub-factors that are related to TIDES:
MAJORFACTOR
1. TIDESR E V I E W !
MAJORFACTOR
2. WAVES
SUB-FACTORS a. Wave shock
b. Increased submergence
Sub-factors that are caused by WAVES:
MAJORFACTOR
2. WAVES
Sub-factors that are caused by WAVES:a. Wave shock
Wave shock is the pounding and shearing force of the water as it rushes
across the intertidal organisms.
MAJORFACTOR
2. WAVES
HERE !Imagine you were anintertidal organism living….
a. Wave shock
Sub-factors that are caused by WAVES:b. Increased submergence
Waves move waterfarther up the beach and
expand the intertidal zone.
MAJORFACTOR
2. WAVES
MAJORFACTOR
2. WAVES
Zones are expandedand shifted landward.
Left side =protected beach
Right side =exposed beach
Sub-factors that are caused by WAVES:b. Increased submergence
Intertidal zones are expandedand shifted upward on beachesexposed to waves as compared
to beaches protected from waves.
MAJORFACTOR
2. WAVES
SUB-FACTORS a. Wave shock
b. Increased submergence
Sub-factors that are caused by WAVES:
MAJORFACTOR
2. WAVES R E V I E W !
MAJORFACTOR
3. SLOPE of the beach.
The term slope refers to the angle at which the sea meets the substrate.
The intertidal zone may vary from shear vertical cliffs, rock faces and pier pilings with an effective slope of 90O, to broad sand or mud flat region which is nearly
horizontal, a slope nearly 0O .
MAJORFACTOR
3. SLOPE of the beach.
90O
45O
0O
MAJORFACTOR
3. SLOPE of the beach.The slope of a beach may widen vertical zones on a horizontal beach or compress zones on a
vertical beach.
Associated factors which may be influenced by beach slope include the effects of wave action,
submergence time, various types of interspecific predation, competition for living
space, and the settlement of larvae.
MAJORFACTOR
3. SLOPE of the beach.
Slope andzonation.
Note narrowzones as beach
nears vertical, andwide zones asbeach nearshorizontal.
MAJORFACTOR
4. SUBSTRATE TYPE
Rocky shore Sandy shore
Beaches are made of different materials.
SUB-FACTORS
a. Attachment of larvae
b. Porosity of substrate
c. Movement of substrate
MAJORFACTOR
4. SUBSTRATE TYPESub-factors of the
SUBSTRATE TYPE:
MAJORFACTOR
4. SUBSTRATE TYPEa. Attachment of larvae
Many larvae have theability to detect thesubstrate type andmay delay their settle-ment until a preferredsubstrate type hasbeen reached.
The substratedetermines wherelarvae settle out, attach and grow.This shapes the nature of zones.
MAJORFACTOR
4. SUBSTRATE TYPEa. Attachment of larvae
MAJORFACTOR
If an organism requires more moisture, it may survive on rock surfaces which are porous and may die on surfaces which
are not so porous.
4. SUBSTRATE TYPEb. Porosity of the substrate
Different substrateshold different amounts
of water.
MAJORFACTOR
4. SUBSTRATE TYPEb. Porosity of the substrate
The porosity, or amount of space within asubstrate, determines the amount
of water that substrate can hold. This results indifferent patterns of zonation on beaches
with different kinds of substrates.
The success of many intertidal organisms is directly related to the frequency of substrate
movement.
If the substrate moves or shifts around regularly, it is a less stable environment.
MAJORFACTOR
4. SUBSTRATE TYPEc. Movement of the substrate
Movement of the substrate.SUB-FACTOR
The larger the substrate particle, the less often it moves. The less often it moves,
the more stable the environment.
MAJORFACTOR
4. SUBSTRATE TYPEc. Movement of the substrate
R E V I E W !
SUB-FACTORS
a. Attachment of larvae
b. Porosity of substrate
c. Movement of substrate
MAJORFACTOR
4. SUBSTRATE TYPESub-factors that are causedby the SUBSTRATE TYPE:
REVIEW OUTLINE:
A. THE INTERTIDAL ZONE & ZONATIONB. FACTORS CONTROLLING ZONATION 1. Tides
a. Activity cycles & inter-specific competitionb. Desiccationc. Temperatured. Terrestrial & atmospheric forces
2. Wavesa. Wave shockb. Increased submergence
3. Slope of the shore 4. Substrate type
a. Attachment of larvaeb. Porosity of substratec. Movement of substrate
T H EE N D