inertidal ok

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Welcome to the Intertidal Zone!

The Intertidal Zone is where the land meets the sea. It is the area betweenhigh tide and low tide. Intertidal communities can be found on sandy beaches,

in bays and estuaries, and along rocky shorelines. The rocky shores are themost diverse and highly populated. In this area

where rocks are covered and uncovered dailyby the ocean, unique and diverse tide poolcommunities are formed.

The marine animals living in this zone are

unique because of their ability to withstandexposure to air and the force of the pounding

waves. The lowest levels of the Intertidal Zoneare the most crowded with life and the higher,dryer levels are less populated. The organism's

adaptations depend on where in the IntertidalZone it will be found.

Low tide in the

intertidal zone.

An Inhospitable, Changing Environment:Much of this inhospitable environment is washed by the tides each day, so

organisms that live here are adapted to huge daily changes in moisture,temperature, turbulence (from the water), and salinity.

Moisture: The littoral zone is covered with salt water at high tides, andit is exposed to the air at low tides; the height of the tide exposes moreor less land to this daily tide cycle. Organisms must be adapted to both

very wet and very dry conditions. 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. Manyintertidal animals burrow into the sand

(like clams), live under rocks, or attachthemselves to rocks (like barnacles andmussels).

Temperature: The temperature rangesfrom the moderate temperature of thewater to air temperatures that vary from below freezing to scorching.

Waves and currents

are strong forces.

Salinity: Depressions on the shores sometimes form tide pools, areasthat remain wet, although they are not long-lasting features. The

salinity of tidepools varies from the salinity of the sea to much lesssalty, when rainwater or runoff dilutes it. Animals must adapt theirsystems to these variations. Some fish, like sculpin and blennies, live in

tide pools.

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The Types of Zones

Spray ZoneWave-spray nourishes life here. This zone could be considered the "desert" of

the intertidal community. Small acorn barnacles, lichens, periwinkle, rocklouse, limpets and algae and a few other species live in this sun-scorched

zone.

Upper Intertidal ZoneSea water reaches this zone only during high tides. Here, you will find life thatregularly survives two long droughts each day. Limpets survive by feeding on

algae. They suction their shells tight to rocks for protection from the waves

and sun. Sea lettuce and other marine algae thrive in this extreme zone.

Middle Intertidal ZoneSea water regularly floods this zone. This turbulent area is covered anduncovered twice a day with salt water from the tides. Species found in this

zone include sea stars, broken-back shrimp, small fish, hermit crabs,nudibranchs and a variety of sea plants.

Lower Intertidal ZoneThis zone becomes dry only during the lowest tides. The intertidal's greatest

diversity of life thrives in this stable region. Here you can find sea stars,nudibranchs, giant anemones and many other fauna.

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How do animals adapt to living in thiscommunity?The Intertidal Zone is a very harsh living environment

for organisms because its ever changing conditions.Animals in this zone are constantly facing challenges

such as varying salinity, drying out by wind andsunlight, predators, strong currents that carry themback to sea, and varying weather conditions. To help

with these difficulties many organisms have specialadaptation features.

A predatorhunting

at low tide.

How do organisms protect themselvesfrom drying out?Some animals, such as sea urchins, carve holes in the

rocks and hide in these holes that provide moisture

during low tide. Mussels and other shell organismswill tightly close their shell to keep in moisture.Snails secrete a slime that gives them moistureduring the long hours of low tide and anemones will

fold in their tentacles to hold in moisture. Each ofthese techniques help the creatures from drying out.

How do organisms protect themselves

from crashing waves and currents?

Many animals

have developedsuction cupsto hold fast

to rocks.

Many organisms use rocks to help with this

problem. Sea Stars and anemones have suctioncups, which allow them to latch onto rocks so they

are not carried out to sea. Mussels use a thread-like substance called byssal threads that stick to

the rocks. Anemones have a unique jelly-like body,which can withstand the crashing waves. For the

same reason, sea stars have a strong leatherycoating, and many shell organisms such as

barnacles have hard shell covering. Otheranimals also resort to burrowing in the sand.

How do organisms protect themselvesfrom predators?As stated previously sea urchins carve holes in

rocks and can hide in these holes. Snails can alsocarve places for protection in rocks. Many otherorganisms, such as periwinkles and crabs, can hide

in cracks and crevices of the rocks for shelter.

Hermit crabs canhide in their shell

and in cracksand crevices.

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Intertidal Animals:

losehtly

n.

Clams have two

shells that areattached by a

muscular hinge.

When a clam is

threatened, itwill pull its softbody into the

shells and cthe shells tig

for protectioMost brittle stars have five long, thin, spiny

arms that radiate from a flat central disk; thearms do not touch each other at their bases.

The hermit crab is a type ofcrab that

doesn't have a very hard shell. Not a truecrab, it uses other animals' old shells for

protection; they especially like old whelkhells. As the hermit crabs grows in size, it

must find a larger shell.

Crabs have ten jointed legs, two of which

have large, grasping claws. They have a

flattened body, two feelers, and two eyes

located at the ends of stalks.

Limpets cling tightly to a rock (using themuscular foot). During the day, limpets

move around by rippling the muscles of thefoot in a wave-like fashion, looking for food.

They return to the same place on their rockeach night. No one knows exactly how they

find th

eir way back to the same spot eachtime.

One of two big claws used for defense and

food handling. In male fiddler crabs, onecheliped is much bigger than the other; in

females, the

two chelipeds are about theame size.s
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Intertidal Animals:

Adult sea urchins have five-sided radial

symmetry. Their spines are used for protection,for moving, and for trapping drifting algae to

eat. Among the spines are five paired rows oftiny tube feet with suckers that help with

locomotion, capturing food, and holding onto theseafloor.

Sea stars (also known as starfish) arespiny, hard-skinned animals that live on the

rocky sea floor. These invertebrates areNOT fish; they are echinoderms. Sea stars

move very slowly along the sea bed, using

hundreds of tiny tube feet.

Although Sea Anemones look like flowers, they

,

are predatory animals. These invertebrates haveno skeleton at all. They live attached to firm

objects in the seas, usually the sea floor, rockor coral, but they can slide around very slowly.

The Black-faced Blenny is a shallow-waterfish that lives among rocks. This territorial

fish is diurnal (most active by day). It is acarnivore that eats tiny invertebrates. This

fish reproduces from April to July.

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How to make a Simple Fish Trap

Background

In the ocean survival is based upon mainly an organism ability to not be detected. Because of thiswe sometimes think that there are no animals in our tidal pools and intertidal zones. In this activity

you will design and adjust a fish trap for an intertial zone and identify the organisms found theirs.

Materials:12oz. or bigger plastic bottle

Sissors or knife to cut bottle

Duct tapeString

2 3 small buckets

Action

1. After class has discussed what an intertidal zone is, its different zonations and some of thecommon adaptations for living here, give them the materials for the fish trap.

2. Group the class in 3s or 4s to allow discussion and cooperation.3.

Ask groups what adaptations they think will enhance the effectiveness of their trap rangingfrom bottle size, choice of bait and trap positioning in tidal pools.

4. Have the groups complete traps and place them accordingly. Make sure traps are securedto avoid loss by wave action.

5. Leave traps for 15 20 mins. without disturbing them so not to scare off animals. Duringthis time a tour of the zones examining different animals and adaptations is best, it allowsthe students to pair up the theory with hands on knowledge. If handy a few quadrant

sampling could be done.6. Have groups collect traps (be sure to handle animals in a manner not to hurt them) empty

contents into bucket and identify.

7. After all groups have gone, go over what modifications made certain traps more effective,organisms found, emphasizing the economic and biological importance of these areas andneed for conservation.

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