Sunshine StateSTANDARDSSC.B.2.3.2: The studentknows that most ofthe energy used todayis derived from burn-ing stored energycollected by organismsmillions of years ago(e.g., nonrenewablefossil fuels).SC.D.2.3.2: The studentknows the positive andnegative consequencesof human action onthe Earth’s systems.SC.G.2.3.4: The studentunderstands thathumans are a part ofan ecosystem and theiractivities may deliber-ately or inadvertentlyalter the equilibriumin ecosystems.

170 Unit 1: Earth’s Waters

EXPLORE Ocean Pollution

How do oil spills affect birds?

PROCEDURE

Fill the bowl with water.

Carefully place the feather on top of the water in the bowl.

Holding the end of the feather, blow on it to try to make the feather rise up out of thebowl. Record your observations.

Remove the feather and place three spoonfuls ofoil into the bowl.

Repeat steps 2 and 3.

WHAT DO YOU THINK?• How did the oil in the water affect the feather?• Based on your findings, how do you think oil

spills might affect birds?

5

4

3

2

1

The ocean supports living resources.The ocean’s many algae and animals are important food sources forpeople in many areas of the world, including the United States. In fact,the United States is the third largest consumer of seafood in the world.The ocean also supports living resources you do not eat for dinner.You have already read about phytoplankton, tiny ocean organisms.Phytoplankton are a very important resource because they producemuch of the oxygen in Earth’s air. Chemicals from other ocean organisms are used in medicines—including some that treat cancer.As research continues, scientists may find even more useful chemicalsin ocean organisms.

VOCABULARYoverfishing p. 171by-catch p. 172

BEFORE, you learned

• The waters near shore supportdiverse life forms

• The ocean environmentchanges with depth

NOW, you will learn

• What living resources theocean contains

• What mineral, energy, and otherresources the ocean contains

• How pollution affects the ocean

KEY CONCEPT

The ocean containsnatural resources.

MAIN IDEA WEBRemember to start amain idea web in yournotebook for the blueheading.

MATERIALS• bowl• water• feather• spoon• cooking

oil

VOCABULARYYou can use a descriptionwheel to take notesabout the term overfishing.

Seafood and AlgaeAcross the United States, supermarkets sell ocean fish and shellfish.Most people, whether they realize it or not, eat seaweeds, too. Theseocean algae are commonly used to thicken cheese, ice cream, and pudding. Seaweeds are also ingredients in nonfood products such asshaving cream and pesticides.

When you think of fishing, you might think of a person with a fishing pole catching one fish at a time. This method of fishing,however, is far too slow and inefficient for the commercial fishingindustry to use. Instead, the fishing industry uses huge nets biggerthan football fields or lines of fishing hooks kilometers long to catchlarge amounts of fish at a time. As you read this sentence, tens ofthousands of nets and fishing lines trail in the ocean. The fishingindustry uses sonar, satellites, airplanes, and other technology to findareas in the ocean that contain large numbers of fish.

Overfishing and By-CatchOver the years, people have noticed that there are fewer and fewer fish than there once were. The main cause of the decrease in fish populations is or catching fish at a faster rate than they can reproduce. Cod is one popular food fish that was nearly killed off by overfishing. Cod were once common in the North Atlantic,but now the cod population is very small. All of the world’s fisheries, ormain fishing areas of the ocean, are either overfished or very close tobeing overfished. Overfishing is a major threat to ocean environments.

overfishing,

Chapter 5: Ocean Environments 171

Overfishing

SOURCE: Census of Marine Life

Mea

n nu

mbe

r of

fish

per

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hoo

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Year

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1958

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1990

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What can you conclude about thenumber of yellowfin tuna left by 1999?

The bar graph shows data from fishing boats thatuse longlines of baited hooks. The data show howmany yellowfin tuna were caught in the subtropicalAtlantic Ocean for every 100 hooks used.

Fishing nets catch nearly everything in their path. A net that isbeing used to catch shrimp, for example, may also catch fish, turtles,sharks, dolphins, and other sea animals. The extra catch—everythingbesides the shrimp—gets tossed back into the ocean either dead ordying. or by-kill, is the portion of animals that are caught ina net and then thrown away. Sometimes the by-catch is greater thanthe portion of fish or other animals the net is meant to catch.

To help reduce by-catch, fisheries started using nets designed toprevent animals such as turtles and dolphins from getting caught.Although these efforts have lessened the number of turtles and dolphins caught in fishing nets, fisheries worldwide still throw awayabout 30 percent of the fish they catch.

check your reading What harm does overfishing cause?

Saltwater AquacultureAs you read in Chapter 3, aquaculture is the farming of both freshwaterand ocean organisms. Saltwater farmers may raise fish, oysters, mussels,shrimp, seaweeds, or other organisms.

Most aquaculture harms the environment.Huge amounts of fish waste are often releasedinto the ocean waters surrounding fish farms,causing damage to plants and animals. Nutrientsand chemicals added to water at fish farms mayalso end up in the ocean. Sometimes plants andanimals are cleared from an area to make spacefor aquaculture. About half of the world’s man-grove forests have been cleared for shrimp farmsand similar uses.

Some methods of aquaculture cause moredamage than others. For 4000 years, farmers inChina have raised fish without causing muchharm. Chinese fish farms are often small, so they release less waste than larger farms.

By-catch,

172

Everything except theshrimp will be thrownaway as by-catch fromthis boat in the Gulf of Mexico.

A shrimp farm extendsout into the water off theisland of Bora Bora inFrench Polynesia.

Chapter 5: Ocean Environments 173

Oil is pumped from theocean floor at hugeanchored platforms such asthis one in the North Sea.

The ocean contains nonliving resources.Ocean water itself is a valuable resource for people living in regionswith little fresh water. As you read in Chapter 3, desalination is theprocess by which salt is removed from seawater. Desalinated seawateris a major portion of the fresh water used by many Middle Easterncountries, such as Saudi Arabia.

Many of the natural resources found on land are also found in theocean. It is often less expensive to remove resources from the landthan from the ocean, so many of the ocean’s resources are not currentlymined. However, as resources on land are used up and new technologymakes ocean exploration and mining easier, ocean mining may increase.

Energy ResourcesOil and gas form from the remains of living organisms. In the ocean,organisms are concentrated in the waters over the continental shelf.Oil deposits, therefore, are found near shore. Oil and gas are pumpedfrom the continental shelf of every continent but Antarctica. About 30percent of the world’s oil is pumped from deposits under the ocean floor.

Huge anchored platforms serve as artificial islands that houseworkers and the necessary equipment for drilling offshore oil wells.The platforms are built to withstand ocean currents, tides, and weatherconditions such as storms. Underwater pipelines carry the oil to shore.

Tankers loadoil and gasat buoys.

Offshore Drilling

Oil and gas arepiped to shore.

Oil and natural gasare pumped up to theplatform, separated,and then pumpeddown to storage tankson the sea floor.

natural gasreservoir

storagetanks

oil reservoir

174 Unit 1: Earth’s Waters

Minerals and RocksWhen rivers empty into the sea, sediments carried by the rivers dropto the bottom. These sediments may contain phosphorite, iron, copper,lead, gold, tin, diamonds, and other minerals. Because these mineralswash into the ocean from land, most of them are found in areas nearshore. It is currently too expensiveto mine many of these minerals.

Some minerals are found awayfrom shore. Nodules (NAHJ-oolz)are lumps of minerals that arescattered across the deep-oceanfloor. The nodules are small atfirst, but they can build up overmillions of years to a size of asmuch as a meter across. Nodulescontain valuable manganese, iron,and cobalt, which are used to make metals such as steel. Nodules arenot mined because it would be very expensive to remove them fromthe ocean floor. In the future, however, nodules may be removed—perhaps with giant vacuums.

The ocean floor contains valuable energy and mineral resources.

The Ocean’s Energy and Mineral Resources

Which ocean environment contains most of the known energy andmineral resources?

Oil and gas

Nodules

Diamonds

Gold

Tin

Phosphorite

Nodules are found away from thecoast on the deep-ocean floor.

A mineral you eat is also removed from the ocean. About one-thirdof the world’s table salt comes from the ocean. Ocean water is left to evaporate in flat, shallow areas. As the water evaporates, salts are left behind.

Sand and gravel might not be the first things you think of whenyou think of important resources. However, they are building materialsused in concrete and cement. Sand and gravel are currently scrapedoff the sea floor in many locations near shore.

Pollution affects the ocean.Every part of the ocean is polluted. Solid waste—such as plastic garbage,tar balls, and hypodermic needles—is a visible form of pollution alongocean shorelines. Trash washes up on beaches worldwide, even on thebeaches of remote islands. Sea animals may mistake trash for food andeat plastic that can block their digestive systems. Animals also get tangledin and even strangled by plastic waste.

Most ocean pollution is harder to see than solid waste.Chemical pollutants, nuclear wastes, and heavy metals likemercury and lead are found in all parts of the ocean.These pollutants are known to harm and kill ocean life.They are also harmful to humans. Pregnant women aresometimes advised not to eat tuna and other fish because the fish may contain low levels of toxic mercury.Although the small amounts of mercury may not harm an adult, they could damage the developing child.

Human waste, sewage, and fertilizers have caused deadzones in the ocean—areas where no plants or animals canlive. These pollutants contain nutrients and cause a hugeincrease in the amount of algae that live in an area. When thealgae die, bacteria consume them. The large numbers ofbacteria use up all the oxygen in an area of ocean. Withoutoxygen, the animals in the area cannot survive.

Although you may notsee this much garbage onevery beach, trash washesup on beaches all over theworld—even on remoteislands.

Each of these mounds is apile of salt harvested fromocean water in Thailand.

175

When oceanwater evaporates,salt is left behind.

Some pollutants are dumped directly into the ocean. Many otherpollutants wash from the land into the ocean or into rivers that flowinto the ocean. Although oil spills are dramatic events that kill manyanimals, they account for only a small percentage of the oil pollutionin the ocean. More oil enters the ocean by washing off the land thanby being spilled. In addition to oil, pesticides, fertilizers, and manyother pollutants wash into the ocean from land.

check your reading What is the source of most of the ocean’s oil pollution?

Preventing Ocean PollutionOcean pollution can be prevented or reduced. In 1988, for example, theUnited States government restricted the use of a harmful chemical thathad been used in ship paint. As a result, levels of the chemical droppedin certain areas of the ocean, and the health of some types of sea life,such as oysters, improved. Government organizations have also bannedthe dumping of some chemicals into the ocean. These bans have successfully reduced some kinds of pollution.

Individuals can help prevent or reduce ocean pollution. Many people may not realize that oil or other chemicals dumped in a drainor sewer or on the ground can end up in the ocean. The proper dis-posal of household chemicals and other toxic substances could reduceocean pollution. The Environmental Protection Agency (EPA) hasinformation about the proper disposal of many common chemicals.

RESOURCE CENTERCLASSZONE.COM

Find out more aboutocean pollution and pollution prevention.

Oil spills are dramaticand disastrous events.However, most oil pol-lution in the ocean iswashed in from land.

Sources of Ocean Oil Pollution

SOURCE: Joint Group of Experts on the Scientific Aspects of the Marine Environment, The State of the Marine Environment, UNEP Regional Seas Reports and Studies No. 115 (Nairobi: U.N. Environment Programme, 1990)

Shipping and oil spills 12%

Air pollution 33%

Runoff from land 44%

Ocean dumping 10%

Offshore drilling 1%

176 Unit 1: Earth’s Waters

Chapter 5: Ocean Environments 177

Global Pollution ProblemsRemember that the ocean is a connected global body of water. Oceancurrents circulate water around the globe and carry pollutants to allparts of the ocean. Pollution that occurs in any part of the world canaffect the whole ocean.

The United Nations, through its 1994 Law of the Sea, attempts tomanage ocean resources and to conserve ocean environments. The lawcalls on all countries to enforce pollution controls. It also sets pollutionrules for ships operating in international waters, regulates fishing, andattempts to divide rights to undersea resources. This international lawis an important step toward protecting the ocean and its resources forfuture generations.

check your reading Why is ocean pollution a global problem?

KEY CONCEPTS 1. Describe one living resource

contained in the ocean andhow its use affects the oceanenvironment.

2. Describe one nonlivingresource contained in theocean and how its use affectsthe ocean environment.

3. How does pollution affect theocean?

CRITICAL THINKING4. Connect How could ocean

pollution affect your life?

5. Sequence Describe how oilfrom a car many miles awayfrom the shore could reach the ocean.

CHALLENGE6. Evaluate Most of the ocean

does not belong to any countryor government. Who do youthink should be responsible for limiting pollution in areasoutside country borders?Who should be able to claimownership of resources inthese areas?

Some oyster populationsrecovered after the use ofa toxic chemical in shippaint was restricted. Thisphoto shows an oysterfarm in Washington State.

oyster