Download 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
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
•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
•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
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,
•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
•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)
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
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.
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).
The temperature ranges from the moderate temperature of the
water to air temperatures that vary from below freezing to
scorching.
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.
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.