myfirstlibraryofknowledge ocean lifegreat whiteshark sharks therearemorethan 350differentkindsof...

My First Library of Knowledge

OceanLife

Orpheus

YCE/Oceans FINAL:YCE/Oceans FINAL 10/26/10 5:41 PM

MORE than two-thirds of the

Earth’s surface is coveredby ocean waters.Theyare home to manydifferent kinds of animals.Most ocean life is foundclose to the surface,where sunlight can passthrough the water. Below200 metres, very littlelight gets through. Only afew creatures can live inthe dark, near-freezingdepths of the ocean.

CONTENTS INTRODUCTIONFirst published in 2006 by Orpheus Books Ltd.,

2 Church Green,Witney, Oxfordshire, OX28 4AW

Copyright © 2006 Orpheus Books Ltd.

Created and produced by Rachel Coombs,

Nicholas Harris, Sarah Hartley and

Emma Helbrough, Orpheus Books Ltd.

Text Emma Helbrough

Consultants Drs John and Margaret Rostron

Illustrated by Betti Ferrero, Ian Jackson, Ray

Grinaway, Peter Dennis, Gary Hincks, DavidWright

and Jim Channell

All rights reserved. No part of this book may be

reproduced, stored in a retrieval system, or transmitted

in any form or by any means, electronic, mechanical,

photocopying, recording or otherwise, without the prior

written permission of the copyright owner.

ISBN 1 901323 XX X

A CIP record for this book is available from the

British Library.

Printed and bound in Singapore.

4 THE WORLD’S OCEANS

6 THE OCEAN FLOOR

8 COASTS, WAVES ANDTIDES

10 SEASHORE LIFE

12 CORAL REEFS

14 FISH

16 SHARKS

18 OCTOPUSES ANDSQUID

20 WHALES ANDDOLPHINS

22 OCEAN MIGRATION

24 DEEPWATER LIFE

26 ARCTIC WATERS

28 OCEAN EXPLORERS

30 UNDERSEAARCHAEOLOGY

32 INDEX

YCE/Oceans FINAL:YCE/Oceans FINAL 10/26/10 5:41 PM

54

Red arrows represent warmocean currents; blue arrowsrepresent cold currents.

THE WORLD’S OCEANS

EARTH has five oceans.Areasof the oceans partly enclosed

by the land are called seas.

OCEAN CURRENTSThe ocean waters move aroundthe globe in huge swirlingcurrents. Surface currents aredriven by the winds.They flow in

roughly circular patterns: clockwisein the northern hemisphere andanticlockwise in the southernhemisphere. Some currents arewarm while others are cold.

NORTH AMERICA

ARCTIC OCEAN

PACIFIC OCEAN

ATLANTICOCEAN

INDIANOCEAN

PACIFICOCEAN

SOUTHAMERICA

AFRICA

EUROPE

ASIA

AUSTRALASIA

SOUTHERN OCEAN

BeringSea

HudsonBay

Baffin Bay

NorwegianSea

NorthSea

Sea ofOkhotsk

Sea ofOkhotsk

Mediterranean Sea

ArabianSea

BlackSea

RedSea

Gulf ofGuinea

Bay ofBengal

SouthChinaSea

TasmanSea

TasmanSea

Gulf ofMexico

CaribbeanSea

ArafuraSea

CoralSea

CoralSea

Gulf ofAlaska

Barents Sea

EastChinaSea

Kara Sea Laptev SeaEast Siberian

Sea

BeringSea

Beaufort Sea

JavaSea

Sea ofJapan

BalticSea

ANTARCTICAWeddellSea

YCE/Oceans FINAL:YCE/Oceans FINAL 10/26/10 5:41 PM Page 4

abyssal plain.There arealso deep gashes in it,called ocean trenches.The abyssal plain isdotted withmountains. Somehigh peaks pokeup above thewaters toform islands.

BLACK SMOKERSIn some places along themid-oceanic ridge, hotwater jets up through tall“chimneys”, called blacksmokers. Strange animalslive down here, including

red worms thatlive in white

tubeshells.

THE OCEAN FLOOR

BENEATH the oceanwaters there are vast

plains and long mountainranges. Skirting the land,there is a ledge called thecontinental shelf. Fromhere, the ocean bed slopesdown to the abyssal plain.A long, jagged ridge runsdown the middle of the

Continentalshelf

Abyssalplain

Mid-oceanicridge

Oceantrench

Seamounts

Islands

ATLANTICOCEAN

ARCTIC OCEAN

SOUTH AMERICA

N O R T HAM E R I C A

A F R I C A

E U R O P E

76


TIDESSea levels rise and fall twice aday.This pattern is known as thetides.They are caused by gravity:the attraction that a large object(in this case, the Moon) can haveover something else.As the Earthspins, the ocean waters on theside of the Earth closest to theMoon (and the opposite side)bulge outwards.This results in a

high tide.The restof the Earth hasa low tide.

Sun

Neap tides Spring tides

Sun

Moon

Moon

Earth Earth

When the Sun and Moon lineup, the Sun’s gravity increasesthe pull.This results in extremelyhigh and low tides (spring tides).When the Sun and Moon are atright angles, the extremes are attheir lowest (neap tides)

COASTS, WAVES AND TIDES

THE OCEAN meetsland at the coast.

Some coastlines areshaped by the action ofwaves crashing against

8 9

Sea currentsmay carry sand and

shingle from one part of theseashore to another. When the currentslows, the sand or shingle is laid down.A spit may form across a bay or estuary.

Beach

Stack

Spit

Arch

Estuary

Sometimeswaves maycarve a hole, orarch, right through aheadland. If the roof of thearch later collapses, part of isleft standing alone in the sea.This is called a stack.

River

WAVES

When the windblows across thesurface of the sea,it turns the waterover and over incircles.These are waves.Waves can travel for manykilometres before breaking on theseashore.As a wave approaches theshore, its lower part drags along the seabed, slowing it down.The top partcontinues moving quickly. It eventuallytopples over or “breaks”.

Headland

Cliff

them, wearing away therocks.Along others, sandand shingle are piled upin beaches or mudflats.

Salt marshes form close tosheltered, muddy shoresaround river estuaries.

They provide richfeeding grounds

for birdsand otherwildlife.

Salt marsh

Dunes


SEASHORE L IFE

SEASHORE life mustbe able to survive thetides (see page 9). They arecovered by salt waterwhen the tide comes in,and left out in the openair when the tide goesout again.

Some animals burrowinto the sand or mud,where they can stay cooland moist. On rockyshores, limpets attachthemselves to rocks.Theykeep moisture under theirshell to stop drying out.

10 11

SEAWEEDSeaweeds do not put downroots into the ground likeplants. Instead, they attachthemselves to rocks. Some kindsstay moist even after the tidehas gone out.They providesmall animals with cool, dampshelter from the sun whilethe tide is out, as well asa source of food.

Oystercatcher

Limpet

Blenny

Sea urchinPrawn

Whelk

Mussels

Hermit crab

Butterfish

Beadletanemone

Sea lettuce

Starfish

Herring gull

Oystercatchers usetheir long beaks toprobe through thesand and rock-pools in searchof food.

Fish, anemones, starfish, seaurchins and other marine lifemay survive in rockpools atlow tide. Gulls will take

almost any food theyfind on the seashore.

Paintedtopshell

Brittlestar


CORAL REEFS

CORAL grows inshallow, warm

waters in tropicalregions. Over manyyears, huge banks ofcoral, called reefs, buildup just below the wavesalong rocky coastlines.

ATOLLSSome coral reefs form rings,called atolls.The coralbuilds up around the edgesof sea volcanoes. Over time,the volcanoes sink belowthe ocean waters.

WHAT IS CORAL?Coral is made from theskeletons of tiny animalscalled polyps.They livetogether in vast numbers.Different kinds of polypsmake coral in all shapesand colours. Some looklike fans, feathers orflowers. One type isshaped like a brain!

CORAL REEF WILDLIFE

Coral reefs are rich with wildlife,including fish, starfish, clams andsea slugs. Some fish feed on theplentiful tiny plants and animals,called plankton, that float in thenearby waters. Others, such as theparrotfish, eat the coral itself.Sharks and barracudas prey on thesmaller fish that live close to thereef.The moray eel hides in waitfor a passing fish or octopus.

Barracuda

Green turtle

Stingray

Giantclam

Parrotfish

Tubesponge

Reef shark

Sea slugs

Sea urchin

Octopus

Starfish Coral

Coral

Coral

Coral

Coral

Napoleonfish

Surgeonfish

Butterflyfish

Grouper

Morayeel

12


14 15

LIVING UNDERWATERMany fish, like the tuna (below), have stream-lined bodies with fins, a tail and a coat ofoverlapping scales.They breathe using gills.They draw water, which contains oxygen, intotheir mouths.When they pump it out throughslits in the sides of their head, their gills absorbthe oxygen. Most fish lay thousands of eggs inthe water, although many of them are eatenby predators before they hatch.

Long-hornedcowfish eat crabsand shrimp. Touncover them, theyblow jets of waterinto the sand.

The conger eel,which grows upto 2.7 m long, hasa scale-less body.

F ISH

PROTECTIONSome fish swim about in large groups,called shoals, for protection frompredators. Others hide amongstrocks and seaweed. Many haveno need to hide at all, as they arepoisonous.Their bright markingswarn others not to eat them.

Bluefintuna

Porcupinefish inflatetheir spinybodies likea balloon toscare offpredators.

THERE are two maintypes of fish:

sharks and their relatives,and bony fish.Theyrange in size fromseveral metres to lessthan one centimetre.

Conger eel

Long-hornedcowfish

Zebra lionfish

UNSEEN KILLERThe stonefish is one of thedeadliest fish. Lying in waiton the sea bed, perfectlycamouflaged among thestones, it injects poison intoanything that touches it. Itcan injure or even kill anyperson unlucky enough tostep on it.

The colourful stripedbody of the zebralionfish warns itsenemies that itsspines are equippedwith deadly venom.

The femaleseahorselays hereggs intoa pouchon themale’sbellyforsafe-keeping

Reefstonefish

Porcupinefish


SMALL SHARKSMost kinds of shark are small.Thenurse shark feeds on bottom-dwelling

creatures in shallow waters.Thegoblin and cookiecutter

sharks inhabit muchgreater depths.

Greatwhite shark

SHARKS

THERE are more than350 different kinds of

shark. Some, such as thegreat white, are fiercepredators. Besides otherfish and squid, they alsohunt turtles and mammalssuch as seals.Whale sharksand basking sharks aregentle giants that feedonly on plankton.

16

Whale sharks are the world’slargest fish. They can grow toover 15 m long. Despite theirgreat size, they are harmless tohumans. They eat only smallfish and plankton.Whale shark

Whale shark

SKIN AND BONESA shark’s skin feels like sand-paper. It is covered by tiny,teeth-like scales. Sharks do nothave any bones in their bodies.Instead, their skeletons aremade of tough, flexible gristleor cartilage.

Hammerheadshark

Goblin shark

GREAT WHITE

Great white sharks use theiramazing sense of smell to find prey.They candetect a single drop of blood in a vast amountof water. Great whites have up to 3000 razor-sharp teeth, arranged in several rows.They areperfect for biting off chunks of flesh!

Sawshark

The hammerhead ’s nostrilsand eyes are found on eitherside of its very oddly-shapedhead. The wide head mayincrease its ability to smell.

Sawsharks have along snout with sharpteeth along each side. They useit to rake up crabs from the sea bed.

Cookiecuttershark

Short-tailednurse shark

17


JET PROPULSIONTo make a quick escape, octopusand squid may use jetpropulsion.They suck water intothe body sac behind their eyes,then squirt it out.As thewater shoots out back-wards, the force ofit pushes theanimal fowards.

Giant squid can grow up to 20 metres long.Their streamlined bodies enable them toglide through the water quickly.

This squid’shuge eye

helps it to seeprey in the darkocean depths,where it lives.

OCTOPUS AND SQUID

TOSCARE offpredators, octopus

and squid can changetheir colour in seconds.They are the mostintelligent of all

18

invertebrates (animalswithout backbones).Octopus and squid aremolluscs, related to shellfish,snails and slugs.

ARMS AND TENTACLESOctopus and squid use their longarms for gripping, touching andtasting. Suckers along the underside ofthese arms help them to grip prey andforce it into their beak-like mouth.

19

Common octopus


WHALES AND DOLPHINS

WHALES, dolphinsand porpoises are

marine mammals.Theybreathe through lungs, so,unlike fish, they mustregularly rise to thesurface for air.Theybreathe through the holeson top of their headscalled blowholes.

Humpbackwhalebreaching(leaping out ofthe water)

Blue whale

Killer whale

Common dolphin

Sperm whale

Beaked whale

20

Blue whales are the largest animals onEarth. They can grow to over 30 metreslong. Their tongue alone weighs as muchas an elephant.

Sperm whales dive deeper thanany other whales. They can holdtheir breath for more than anhour. They dive down in search oftheir favourite prey: giant squid.

Many dolphins live ingroups called schools.They call to each otherusing squeaks and clicks.They hunt fish and squidnear the water’s surface.Dolphins often leap outof the water.This may bebe to alert other dolphinsto the presence of food.

BALEEN WHALES

Some whales do not haveteeth. Instead, they have baleenplates: bristle-fringedplates that hang fromtheir upper jaw.Baleen whales,such as humpbacksand blues, feed bygulping mouthfuls ofseawater.They push out the

water through their baleenplates, leaving behind tinycreatures, called krill, whichthey swallow.


MANY marine animalsmake incredibly long

journeys each year to breedin a safe spot or to reachrich feeding grounds.Thegrey whale, for example,spends the summer feedingin Arctic waters. It swimssouth in winter to breed offthe Mexican coast.

OCEAN MIGRATION

2322

Pacific salmon travel thousands ofmiles out to sea and back to their“home” rivers, where they swim

upstream to breed.

Slender-billedshearwater

Arctic tern

Pacificsalmon

Grey whale

Wandering albatross

European eels

Greenturtle

Green turtles feed off Brazilbut swim across theAtlantic Ocean to laytheir eggs onAscension island.

The young of European eels swimacross the Atlantic to laytheir eggs.

ATLANTICOCEAN

PACIFICOCEAN

Arctictern

Young ofEuropean eel

Green turtle

Pacificsalmon

Greywhale

Wanderingalbatross

Slender-billedshearwater

BIRDSArctic terns breed in the

Arctic during the summer.Then they fly to the Antarcticat the opposite end of the Earth,a distance of 13,000 kilometres,to spend the southern summerfeeding.The wanderingalbatross also circles the world,but around the Southern Oceanwhere the distance is shorter.The slender-billed shearwater,makes a seven-month journeyaround the north Pacific Oceaneach year.


25

DEEPWATERL IFE

DEEP in the oceans,below about 200

metres, very little light getsthrough. Here in the“twilight zone” it is darkand cold. Only a fewanimals can survive theseconditions. Some, like thehatchetfish, travel to thesurface every night to feed.Others eat dead animals orplants that sink down fromabove, or prey on eachother. Many deepwatercreatures have long teeth,large mouths, and glowingparts to lure their prey.

24

Jellyfish

Black star-eater

Flashlight fish

Plankton

LoosejawShrimp

Blackdragonfish

HachetfishLanternfish

Starfish

Deepseasquid

Viperfish

Redcombjelly

Vampiresquid

DeepseaanglerfishGulper eel

MAKING LIGHTSome sea creatures are able tomake light inside their bodies.This is called bioluminescence.Some creatures make light to seeor to attract prey towards them.Others use light in their defence.For instance, when comb jelliesare attacked, they produce abright light which temporarilyblinds their attacker.This givesthem a chance to escape.


MUCH of the ArcticOcean is covered

by a thick layer offloating ice all year round.In summer, when Arcticwaters are teeming withtiny animals and plants,fish, seals, whales and seabirds hunt for their food.

WALRUSES AND SEALSWalruses and seals have a thicklayer of blubber under their skinto keep them warm.Theirflippers make them excellentswimmers and divers.Walruses

search the sea bed for crabsand shellfish to eat. Male

walruses use their tusks asweapons when fightingover females.

ARCTIC WATERS

NARWHALSNarwhals are related towhales and dolphins.They

feed on squid, crabs and fish.Themales have a long tusk, actually a

tooth growing out of their top lip. It is notclear what this tusk is for, but it may be usedlike a sword for fighting over females.Walrus

POLAR BEARSPolar bears spend most ofthe year on floating ice,where they hunt seals.Theyhave a thick, whitewaterproof coat whichcamouflages them againstthe ice.Their strong clawsand hairs on the soles oftheir feet give them a goodgrip as they roam the icealone. Polar bears areexpert swimmers and canswim for hours at a timewithout needing to rest.

Narwhal

Beardedseal

Polar bear

26


SUBMERSIBLESMarine scientists sometimes useminiature submarines calledsubmersibles to learn more aboutocean life and explore the oceanfloor.A submersible has thick metalwalls to protect the crew inside.Bright spotlights help them see inthe darkness.Various roboticattachments enable them to takephotographs and gather samples.

OCEAN EXPLORERS

THE DEEPER in the ocean yougo, the greater the weight of

water pressing down on you fromabove. Below 50 metres, this pressure istoo great for most divers. Robots canbe used for deepwater exploration.

28

Submersible exploringa shipwreck

Robot

29


UNDERSEAARCHAEOLOGY

MARINE archaeologistsare scientists who search

for and recover relics fromshipwrecks—and evensubmerged cities. Fromcareful excavation, divershave found coins, guns,clothes and shoes, whichcan tell them a lotabout life in the past.

31

DISCOVERING A SHIPWRECKTo locate a shipwreck, archaeologistsstudy historical records.These mayonly provide a rough idea of awreck’s position, so the area mustthen be scanned. Modern detectionequipment includes sonar, which usessound waves to locate objects. Oncea site has been pinpointed, divers setup a grid of poles, which divides thesite into squares to record whereobjects are found.After photos are

taken, finds can be takento the surface.

30

Raising a cannon

Recovering atreasure chest

Clearing awaysediment withsuction pipes

Sketchingthe site

Filming theexcavation

Takingphotographs

Carryingfinds to thesurface

Recordingwhere objectswere found


INDEXAabyssal plain 6-7albatross, wandering22-23

anglerfish, deepsea 25arch 8archaeology, marine30-31

Arctic Ocean 4, 7, 22-23,26-27

Atlantic Ocean 4, 7, 22atolls 12

Bbarracuda 13beaches 8bear, polar 27bioluminescence 24-25birds 9, 10-11, 23, 26black smokers 6blenny 10blowholes 20breaching 21brittlestar 11butterfish 11butterflyfish 12

Cclam, giant 13coasts 8-9, 10-11, 12comb jelly, red 24-25continental shelf 6-7coral 12-13coral reefs 12-13cowfish, long-horned 14crab, hermit 11crabs 17, 26-27currents 4-5, 9

Ddivers 28, 30-31dolphin, common 21dolphins 20-21dragonfish, black 25

EFeel,conger 14European 22

gulper 25moray 12

egg laying,in fish 15, 22in turtles 22

estuaries 9fish 10-17, 20, 24-27flashlight fish 25

GHgills 15gravity 9grouper 13gull, herring 11hatchetfish 24-25

IJice 26-27Indian Ocean 5invertebrates 18islands 6jellyfish 24

KLkrill 20lanternfish 24limpet 10lionfish, zebra 14loosejaw 25

MNmolluscs 18Moon 9mudflats 8-9mussels 11napoleonfish 12narwhal 27

Ooceans,birds of the 9, 10-11,23, 26

deepwater life in the24-25

exploration of the 28floor of the 6-7, 29glowing creatures inthe 24-25

migration routesacross the 22

of the world 4-5wildlife of the 10-27,29

octopus 13, 18-19common 19

oystercatcher 10

PRPacific Ocean 4-5, 23parrotfish 12-13plankton 13, 16, 25polyps 13porcupinefish 14porpoises 20pressure 28rays 13ridge, mid-oceanic 6-7robots 28-29rockpools 10-11

Ssalmon, Pacific 23salt marshes 9salt water 10sawshark 17sea anemone 11sea lettuce 11sea slug 13sea urchin 10-11, 13seahorse 15seal, bearded 27seals 16, 26-27seamounts 7seas 4-5seashore life 10-11seaweed 11, 14shark,cookiecutter 17goblin 16-17great white 16-17hammerhead 17reef 12short-tailed nurse16-17

whale 17sharks 13, 14, 16-17shearwater, slender-billed23

shellfish 10, 18, 26

shipwrecks 28-31shrimp 25sonar 31Southern Ocean 5, 23spit 9sponge, tube 12squid 18-19, 20, 27deepsea 25giant 19, 21vampire 25

stack 8star-eater, black 25starfish 10-11, 12-13, 24stingray 12stonefish, reef 15submersibles 28-29Sun 9surgeonfish 12

Ttern,Arctic 23tides 9, 10-11treasure 30trench, ocean 6-7tuna, bluefin 15turtle, green 12, 22turtles 16twilight zone 24

Vviperfish 25volcanoes 12

Wwalrus 26waves 8whale,beaked 21blue 20-21grey 22-23humpback 20-21killer 21sperm 21

whales 20-21, 26-27baleen 20

whelk 11winds 5, 8worms 6

32


myfirstlibraryofknowledge ocean lifegreat whiteshark sharks therearemorethan 350differentkindsof...

Documents