The document describes the intertidal zone, where land meets the sea and is alternately submerged and exposed by tides. It is divided into four zones based on tidal exposure: the splash zone, high tide zone, middle tide zone, and low tide zone. Organisms in each zone have adapted to the varying temperatures, salinity, moisture, and sunlight exposure caused by the daily tides. Competition for space is also a major biological factor, as more zones have longer submergence times with greater resources.

1. rt idal Zone
Inte e
ti c Biom
nia Aqua
Califor

2. Intertidal Pool
The area where the land meets the sea, it is
alternatively submerged and exposed by the
daily cycle of tides. The resident organisms are
subject to huge daily variation in temperature,
light intensity, and availability of seawater, which
makes life difficult.

3. Intertidal Zonation
Four Main Zones
Splash Zones : The splash zone is never covered by water and is
only sprayed with saltwater during high tides.
High Intertidal Zone: The high tide zone is covered with saltwater
only during high tides
Middle Intertidal Zone: The mid tide zone is covered and uncovered
twice a day by the tides
Low Intertidal Zone: The low tide zone is only uncovered during the
lowest of tides

5. Intertidal Zones in
California

6. What Causes the Tide?
Tides are created by the gravitational pull of the
moon and, to a lesser extent the sun, upon the
Earth's oceans. The sun has about half the effect
that the moon has on the Earth's tides.
In most areas, typically two high tides and two low
tides occur within a 24 hour and 50-minute lunar day.
(A lunar day is 50 minutes longer than a solar day.)
The time between each high and low tide (or low and
high tide) is 6 hours and 12.5 minutes.

7. Abiotic Factors
Temperature
The temperature of tide pools is affected by air temperature and direct
sunlight on the pool.
Salinity
The sun and wind evaporate water from the surface of pools. In isolated
tide pools, this caused an increase in salinity (salt concentration).

8. Abiotic Factors
Wind
It increases heat loss by evaporation and convection. It also contributes to water loss in
organisms by increasing the rate of evaporation in animals and transpiration in plants.
Light
Most aquatic plants and algae are limited to a fairy narrow zone close to the
surface , where light is sufficient to allow photosynthesis
Moisture
Without moisture there can be no life. Water acts as a solvent for
chemical reactions, takes part in the reactions of hydrolysis.

9. Abiotic Factors
Rocks
Sand

10. Biotic Factors
Zone 1: “Splash Zone”
Above the high tide, and is reached only by the
splash of the waves
Adapted to prolonged period exposure to air.
Reproduce independently of water.

11. Zone 1: “Splash Zone”

13. Zone 2: High Tide Zone
Flooded during high tide only.
High saline environment.
Water is not high enough to sustain large
amounts of vegetation, but higher compared to
the “splash zone.”

14. Zone 2: High Tide Zone

16. Zone 3: Middle Tide Zone
The approximate limits of this zone may be
recognized by the development of mussel beds
at the upper level and the patches of the surf
grass at its lower level.
More favorable for many species, and the major
biological factor at work is the competition for
space.
Increased submergence time.

17. Zone 3: Middle Zone

19. Zone 4: Low Tide Zone
Mostly submerged in water.
More marine vegetation.
Organism in this area are not well adopted to periods of
dryness and temperature extremes.
Creatures in this area can grow larger sizes because there is
more available energy available..
Water is shallow enough to allow plenty of light to allow
substantial photosynthesis.
The area is also protected from large predators such as large
fish because of the wave action and water being shallow.

20. Zone 4: Low Tide Zone

22. Intertidal Zone Ecology

23. Advantages
There are a number of advantages to living in a tide pool
ecosystem.
• Algae and other intertidal plants grow in the abundant
sunlight and support an entire food chain of animals.
• Constant wave action supplies the tide pool with
nutrients and oxygen.
• Food is abundant.
• A varied substrate provides hiding places and surfaces
to cling to.

24. Challenges to Living in the
Intertidal Zone
The rapidly changing conditions of a tide pool make
survival a challenge. Exposure to surf and sun varies
considerably.
• Plentiful sunlight, which helps intertidal plant life
grow quickly, can also rapidly dry up precious
moisture and increase the water temperature.
• As the tides rise and fall, the salinity (salt
concentration) constantly changes. Animals living in
the intertidal zone must be able to tolerate wide
salinity variations.

25. Challenges to Living in the
Intertidal Zone
• If sufficient nutrients are available, intertidal
animals reproduce rapidly, so they constantly
compete for space, light, and food.
• Animals are also exposed to predators while
the tide is out.
• Waves that bring in much-needed nutrients and
moisture can also carry unprotected animals out
to sea.

26. Adaptations
Small animals that live in the splash zone can avoid desiccation by
closing their shells tightly to seal in moisture.
The strong pounding of waves caused a major problem. Some, like
sea stars, cling fast to the rocky surfaces; others find shelter in
crevices or hide under thick mats of seaweed when the tide is out.
Some species may eviscerate.
Some animals secrete a glue-like mucus to stick to the rock's
surface.
Many fishes that inhabit tide pools, such a sculpin and young
opaleyes, can breathe air at the surface