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Written by Trica Oshant Hawkins

Exploring Tide Pools

A Reading A–Z Level R Leveled Reader

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ExploringTide Pools

Exploring Tide PoolsLevel R Leveled Reader© 2003 Learning Page, Inc.Written by Trica Oshant HawkinsIllustrations by Cende Hill

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Written by Trica Oshant HawkinsCorrelation

LEVEL RFountas & Pinnell OReading Recovery 22

DRA 34

ExploringTide Pools

Photo Credits:Front cover: © Brandon D. Cole/CORBIS; back cover, titlepage, pages 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 21, 22:© clipart.com; pages 4, 20: © Royalty-Free/CORBIS; page 5:Scott Walking Adventures/www.scottwalking.com; page 23: © James A. Sugar/CORBIS.

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Table of Contents

What Are Tide Pools? .........................................4

What Causes Tides? ............................................5

The Intertidal Zone .............................................7

What Is Life Like in a Tide Pool?......................8

Drying Out .........................................................12

Eating and Being Eaten ....................................14

What Lives in Tide Pools?................................16

Invertebrates ..................................................16

Fish ..................................................................20

Land Animals.................................................21

Plant-Like Organisms ...................................21

Exploring Tide Pools.........................................22

Glossary ..............................................................24

What Are Tide Pools?

The tide is the rising and falling of theocean where it meets the land. The tide risesand falls twice each day. In some areas, littlepools of seawater are left behind when thetide goes out. These are tide pools. Most tidepools are found in low areas along rockyshorelines. You might also find small tidepools on sandy beaches. Any place along theshoreline that traps water creates a tide pool.

Tide pools are full of sea life.

Earth EarthMoon

Sun

Moon

Sun

Spring Tides Neap Tides

What Causes Tides?

The tides are caused by the force of gravity.The sun and moon have strong gravity thatpulls on Earth. This gravity pulls on both landand water. But only the water can move inresponse to gravity. When the sun and moonpull on Earth, they pull the ocean water intotwo mounds.

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The rotation, or spin, of Earth causes the rising and falling of the tides. As landareas move into and out of where the water is in mounds, the tides slowly rise and fall.Since Earth makes one full rotation each day,there are two high tides and two low tidesevery 24 hours.

The moon also moves around Earth, andthis movement affects the tides. Twice eachmonth, the moon and sun line up. They pullon the ocean water together. Their combinedgravity causes higher mounds of water,creating the highest and lowest tides of themonth. These tides are called spring tides. At other times, the sun and moon pull againsteach other. At these times, the high tides arenot as high, and the low tides are not as low.These are called neap (neep) tides.

Veryhightide

Sun and moon pull together andcause very high and low tides.

Sun and moon pull against eachother and make smaller tides.

VerylowtideGravitational

pullGravitational

pull

A dock with boats at high tide (top),and the same dock at low tide (bottom)

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The Intertidal Zone

The area along the shore between high tide and low tide is the intertidal zone. This area is covered by seawater during hightide and exposed to air during low tide. The area closest to the sea is only exposed to the air during the very lowest tides. The area farthest from the sea is only covered by waterduring the highest tides. Different creatureslive in different parts of the intertidal zone,depending on whether they need air or water.

Low tide High tide

What Is Life Like in a Tide Pool?

Tide pools are full of sea life. You can see these creatures when the tide goes out.Usually, the more places there are for animalsto hide or attach themselves, the moreanimals you will find in a tide pool. The tidepools with the most animals usually occur inrocky areas. The material the animals live inor attach themselves to is called the substrate.In tide pools, the substrate is usually rocks or sand.

The arrows point to theedges of the intertidal zone.

A sea starhangingaround in a tide pool

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Surviving in the intertidal zone is difficultfor the animals there. Imagine living whereseawater washes in and out of your homeevery day! The animals in tide pools have to be able to deal with waves crashing overthem. If they don’t hang on tight or get out of the way, they could be tossed around,battered against rocks, or even swept away.

Intertidal animals have adapted to life inthe tide pools. These animals are used to thetide coming and going from their homes everyday. They have ways of clinging to rocks andfinding protection from crashing waves. Theyhave ways of preventing their bodies fromdrying out in the air. They also have ways ofavoiding the beaks and jaws of predators.

How a tide pool animal survives dependson whether it is stuck in one place or canmove around. Many animals are attached tothe substrate, and they do not move around.This prevents them from being washed away.

Anemones and sea stars haveways to survive in tide pools.

When the tide rises, waves willcrash over these tide pools.

But it isn’t just seawater that threatens theanimals of the intertidal zone. Exposure to theair and sun is also dangerous. For an animalthat needs to be covered by water, exposure to air causes two major problems. The firstproblem is drying out. The second problem is that these animals are suddenly exposed to predators looking for an easy meal. So howdo intertidal-zone animals survive?

Drying Out

Most stationary tide pool creatures havedeveloped ways to protect their bodies fromdrying out. Some animals, such as barnaclesand oysters, have hard shells that they canclose or crawl into during low tide. Once intheir shells, they have enough moisture tokeep from drying out until high tide returns.The stationary animals most in danger ofdrying out are the soft-bodied creatures suchas sea anemones (ah-NEM-oh-nees). Theseanimals are usually found close to the ocean,where the low tide does not uncover them for very long. When the tide is out, they closeup their bodies as much as possible to keepmoisture from escaping.

Some animals, such as mussels, have very strong hair-like fibers that attach to the substrate. Other animals, like barnacles(BAR-nick-els), create cement-like “glue” that they use to attach themselves to rocks.Because they cannotmove around, these animalscannot escape from the sun, air, or predators.

Tide pool animals that are mobile, or can move around, are able to run, swim, and crawl. Some of these creatures are seacreatures that become trapped in tide poolsduring low tide. They cannot return to the sea until the high tide returns. But because

they aremobile, theycan seekshelter fromthe air, sun, and predators.

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Anemones need moisture to survive.

A crab on the move

Barnacles

Eating and Being Eaten

Eating and being eaten are facts of lifeeverywhere, even in tide pools. Tide poolanimals have unique and interesting ways of finding and eating food. Oysters and clams use hair-like parts to trap tiny animalsfloating in the water. Anemones and jellyfishsting tiny animals with their tentacles. Anoctopus uses its strong arms and suction cupsto catch other animals. Crabs and lobsters usetheir claws to pick up food.

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Mobile tide pool animals have a betterchance of survival, since they can move to prevent drying out in the sun and air.Many can dig into the sand, while others seekshelter under rocks or seaweed. A group ofvery thin crabs called slider crabs can slidetheir flat bodies into cracks between rocks.Slow-moving animals such as marine snailscan hide inside their shells. They can actuallyclose a little “trap door” to seal themselvesinside. But usually there is enough water in a tide pool for mobile animals to swim or crawl about.

Crabs can hide inburrows in wet sand.

Crabs feasting ontiny sea creatures

What Lives in Tide Pools?

InvertebratesThe most common kinds of animals in tide

pools are called invertebrates. These animalshave soft bodies and no backbones. Theyrange from creatures such as sponges andcorals to creatures such as octopi and seastars. Invertebrates also include animals suchas anemones, jellyfish, worms, crabs, shrimp,snails, and urchins. Invertebrates can bestationary or mobile. These drawings showinvertebrates commonly found in tide pools.

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SpongesLumpy, irregular bodies

Small holes all over bodies

Stationary; stuck tothe substrate

Flat wormsFlat, worm-like bodies

Mobile

Segmented wormsFlat or round segmentsor sections

Mobile

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Tide pool animals also have amazing waysto avoid being eaten. Often, the way animalsavoid drying out also helps them avoid beingeaten. They simply slide under rocks or slipinto their shells. Other tide pool animals run,scuttle, swim, or even jump to escape hungrypredators. Some tide pool animals blend inwith their surroundings. This helps them hidefrom predators.

Seagulls will eat almost any smallsea creatures they can find.

CoralsHard skeletons or shells

Soft bodies with tentacles

Stationary

AnemonesFlower-shaped bodies

Tentacles with stinging cells

Usually, but not always,stationary

JellyfishBell or dome-shaped bodies

Long tentacles with stinging cells

Mobile

Sea stars, sea urchins,and sand dollarsSpiny skin

Bodies with sectionsarranged in a circle

Can move slowly

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Snails and slugsSoft bodies

Crawl on single “foot”

Clams and oystersSoft bodies

Hard, two-sided shells

Usually stationary, but can move in an emergency

OctopiSoft bodies

Hard beaks

Eight arms

Swim very fast

18

2019

BarnaclesStationary; hard shells stuck to rock

Segmented legs

Shrimp,crabs, andlobstersSegmented legsand bodies

Hard outer shells

Mobile

FishAnother group of animals commonly

found in tide pools is fish, which do havebackbones. There are many types of fish thatare adapted to life in the tide pools. Since tidepools are small compared to the ocean, fishthat live in them are usually small. Other fishaccidentally get trapped in tide pools whenthe tide goes out. These fish are not used toliving in such a small space. They wait untilthe tide returns to swim off in the open sea.

A kelpfish in a tide pool

Exploring Tide Pools

Tide pools are fun to explore. They are likean aquarium full of sea creatures. If you evergo to the ocean, find a place where there aretide pools. The best places to find tide poolsare rocky shores. Pay attention to the risingand falling of the tides. Usually newspapersnear the oceans publish the times and heightsof the tides. Remember, the lower the tide, the more you are likely to see.

When you find a tide pool to explore, thereare some things you can do to help you seemore creatures. It is best to move slowly and gently to avoid stepping on or crushinganimals.

Land AnimalsMany land animals also visit tide pools.

The shallow water in tide pools makes it easyfor these animals to find and eat sea creatures.Many birds, includingseagulls and ravens,eat oysters, mussels,and fish. Mammalssuch as raccoons andmonkeys can scoop upanimals and eat them.

Plant-Like OrganismsThere are also many plant-like organisms

in tide pools. Most of these belong to a groupcalled marine algae. They are also known asseaweed. There are many different types ofseaweed, but only some of them are found

in tide pools. Seaweedprovides good hidingplaces for animals. It alsoprovides a substrate towhich some animals attachthemselves or their eggs.

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Tide pools are full offascinating creatures.

Marine algae, or seaweed

A shorebird eating a shellfish

Glossaryadapted changed or shaped to work

in a certain situation (p. 10)

algae plant-like organisms, includingseaweed (p. 21)

gravity the force that pulls things towardvery large objects (p. 5)

intertidal zone the zone between the highest tide level and the lowest tide level(p. 7)

invertebrates animals without backbones (p. 16)

mobile can move around (p. 11)

neap tides the smallest tides of the monththat happen when the sun andmoon pull against each other (p. 6)

predators animals that hunt and eat otheranimals (p. 9)

rotation spinning (p. 6)

spring tides the greatest tides of the monththat happen when the sun andmoon line up (p. 6)

substrate the material that tide poolsanimals attach themselves to or live in; usually rocks or sand(p. 8)

Sometimes it is a good idea to just stop and closely observe one small area that youfind interesting. The longer you look, the more likely you are to see things.

Remember that the tide pool is home tomany creatures. If you lift up a rock to lookfor creatures, do so gently. Always put rocksback where youfound them. Checkwith an adult if youwant to pick up atide pool animal—some of them cansting! Put somewater in your handfirst to keep theanimal moist. Andalways put seacreatures back whereyou found them.Animals need to stayin their tide poolhomes. They don’tmake good pets and are likely to die if theyare removed from the tide pool.

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Be careful handlingtide pool animals.