Ecology Biomes:

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Ecology Biomes
Intertidal Zone
(Littoral Zone)
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What is the Intertidal Zone?

• Biome Located at the junction of the atmosphere,
  hydrosphere, and lithosphere
• Zone between high tide and low tide where an
  abundance of marine life thrives
• Complex marine ecosystem found along coastlines
  worldwide
• Rich in nutrients and oxygen , making it home
  to a variety of organisms

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• The intertidal zone is further divided into four
  key sub-zones
• Splash/ Spray zone - "desert" of the intertidal
  zone, survives on the mist and spray of the ocean
• Upper intertidal zone - covered by water during
  high tide so it experiences dry periods daily
• Middle intertidal zone - regularly covered with
  sea water
• Lower intertidal zone - dry only during the
  lowest tides and contains the highest
  biodiversity within the intertidal zone

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Sub -zones
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Supralittoral/ Spray Zone

• Located above the spring high tide Line
• Covered by water only during unusually high tides
  and storms
• Sprayed with salt water during high tide (hence
  the name spray zone)
• Size of spray zone depends on slope, splash,
  climate, and amount of shade
• Organisms common to this area Algae, barnacles,
  isopods, lichens, lice, limpets, periwinkles,
  snails whelks
• Little vegetation

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High Tide Zone

• Flooded during High tide only
• Highly saline environment
• Very extreme temperatures due to exposure of land
  to air and then to water
• Organisms common to this area anemones,
  barnacles, brittle stars, chitons, crabs
  (including hermit crabs), Fucus, green algae,
  isopods, limpets, muscles, sea stars, snails,
  whelks
• Some marine vegetation
• Also contains tide/ rock pools which can be
  inhabited by small fish and larger seaweeds

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Tide Pools
residents have many special adaptations. Tide
pools differ from each other depending on depth
and height in the intertidal zone. Anemones,
barnacles, dog whelks, sculpins, and sea urchins
create intricate interactions in these tiny,
isolated micro-habitats.
Each tide pool is a unique environment formed in
rocky depressions by the receding tide. Tide pool
organisms face large and sudden changes in
salinity, temperature, pH and other factors due
to tidal movements. As a result,
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Middle Tide Zone

• Almost equal periods Covered and uncovered by
  water throughout day depending on tide
• Temperatures less extreme due to shorter periods
  of exposure to the sun
• Lower salinity levels
• Organisms are larger and more complex life is
  more diverse
• Major biological factor is competition for space
• Organisms common to this area anemones,
  barnacles, chitons, crabs, green algae, isopods,
  limpets, muscles, sea lettuce, sea palms, sea
  stars, snails, sponges, whelks
• Higher inhabitant of marine vegetation,
  especially seaweeds
• Also contains Tide/ rock pools which can be
  inhabited by small fish, shrimp, krill, sea
  urchins, and zoo plankton

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Low Tide Zone

• Almost always flooded
• Only exposed at Low tide exposed for longer
  amounts of time at extremely low tides
• Great biodiversity larger animals
• organisms not well adapted to periods of dryness
  or extreme temperatures
• Organisms common to this area abalone, anemones,
  brown seaweed chitons, crabs, green algae,
  hydroids, isopods, limpets, muscles, nudibranchs,
  sculpin, sea cucumber, sea lettuce, sea palms,
  sea stars, sea urchins, shrimp, snail, sponges,
  surf grass, tube worms, whelks
• Normal salinity levels and shallow waters to
  allow photosynthesis account for larger more
  abundant vegetation (such as seaweeds)

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Animal and Plant Life

• In the intertidal zone the most common organisms
  are small and most are relatively uncomplicated
  organisms. Reasons include
• intermittent supply of water which marine
  organisms require to survive
• wave action around shore can wash away or
  dislodge poorly suited or ill-adapted organisms
• high exposure to sun causes temperature range to
  be extreme
• salinity is much higher because salt water
  trapped in rock pools evaporates leaving salt
  deposits

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Environmental Factors
Moisture
The littoral zone is covered with salt water at
high tides, and it is exposed to the air at low
tides the height of the tide exposes more or
less land to this daily tide cycle. Organisms
must be adapted to both very wet and very dry
conditions.
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Water Movement
The turbulence of the water is another reason
that this area can be very difficult one in which
to survive - the rough waves can dislodge or
carry away poorly-adapted organisms. Many
intertidal animals burrow into the sand (like
clams), live under rocks, or attach themselves to
rocks (like barnacles and mussels).
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Temperature
The temperature ranges from the moderate
temperature of the water to air temperatures that
vary from below freezing to scorching.
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Salinity
Depressions on the shores sometimes form tide
pools although they are not long-lasting
features. The salinity of tidepools varies from
the salinity of the sea to much less salty, when
rainwater or runoff dilutes it. When salt water
left in tide pools evaporates, all that is left
is salt deposits. the are Animals that must
adapt their systems to these variations. Some
fish, like sculpin and blennies, live in tide
pools.
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Human Impact
Although well-protected against the forces of
nature, the plants and animals of the intertidal
zone are not entirely protected from man. Man's
impact on the intertidal zone can easily disturb
the balance within an intertidal community.
Hazardous chemicals from waste disposal can harm
species that feed on the ocean's bottom. Manmade
or natural oil seepage can clog tidepool animals
so they are unable to live or avoid being eaten.
Careless tidepool explorers can crush animals and
leave others exposed. Unfortunately, the
intertidal zone is a place where changes to the
climate and human impact can have their greatest
impact.