The ocean contains natural resources.

Section 4.3C

The ocean supports living resources.

• The ocean’s many algae and animals are important food sources for people in many areas of the world.

• The U.S. is the third largest consumer of seafood in the world.

• Phytoplankton produce much of the oxygen in Earth’s air.

• Chemicals from other ocean organisms are used in medicine.

Seafood and Algae

• Ocean algae are used to thicken cheese, ice cream, and pudding and are also ingredients in nonfood products such as shaving cream and pesticides.

• The fishing industry uses huge nets bigger than football fields or lines of fishing hooks kilometers long to catch large amounts of fish at a time.

• The fishing industry uses sonar, satellites, airplanes, etc. to find areas in the ocean that contain large numbers of fish.

Overfishing and By-Catch

• There are fewer and fewer fish than there once were because of overfishing, or catching fish at a faster rate than they can reproduce.

• Cod were once common in the North Atlantic, but now the cod population is very small.

• Overfishing is a major threat to ocean environments.

Overfishing and By-Catch

• Because fishing nets catch nearly everything in their path, when fishing for shrimp, you may also catch fish, turtles, sharks, dolphins, etc.

• The extra catch (everything besides the shrimp) gets tossed back into the ocean either dead or dying.

Overfishing and By-Catch

• To help reduce by-catch fisheries started using nets designed to prevent animals such as turtles and dolphins from getting caught.

• Although this helps, fisheries worldwide still throw away about 30 percent of the fish they catch.

Saltwater Aquaculture

• Aquaculture is the farming of both freshwater and ocean organisms.

• Saltwater farmers may raise fish, oysters, mussels, shrimp, seaweeds, or other organisms.

• Salmon farm tour

Most aquaculture harms the environment.

• Huge amounts of fish waste are often released into the ocean waters surrounding fish farms, causing damage to plants and animals.

• Nutrients and chemicals added to water at fish farms also end up in the ocean.

• Sometimes plants and animals are cleared from an area to make space for aquaculture – about half the world’s mangrove forests have been cleared for shrimp farms and similar uses.

• Salmon farming

The ocean contains nonliving resources.

• Desalinated seawater is a major portion of the fresh water used by many Middle Eastern countries, such as Saudi Arabia.

• As resources on land are used up and new technology makes ocean exploration and mining easier, ocean mining may increase.

Energy Resources

• Oil and gas form from the remains of living organisms.

• In the ocean, organisms are concentrated in the waters over the continental shelf.

• Oil and gas are pumped from the continental shelf of every continent but Antarctica.

• About 30% of the world’s oil is pumped from deposits under the ocean floor.

Energy Resources

• Huge anchored platforms serve as artificial islands that house workers and the necessary equipment fro drilling offshore oil wells.

• The platforms are built to withstand ocean currents, tides, and weather conditions.

• Underwater pipelines carry the oil to shore.

Minerals and Rocks

• When rivers empty into the sea, sediments carried by the rivers drop to the bottom.

• These sediments may contain phosphorite, iron, copper, lead, gold, tin, diamonds, and other minerals.

• It is currently too expensive to mine many of these minerals.

Minerals and Rocks

• Some minerals are found away from shore.• Nodules are lumps of minerals that are scattered

across the deep-ocean floor.• They are small at first, but they can build up over

millions of years to a size as much as a meter across.

Nodules• They contain valuable

manganese, iron, and cobalt, which are used to make metals such as steel.

• Nodules are not mined because it would be very expensive to remove them from the ocean floor.

• In the future they may be removed – perhaps with giant vacuums.

Minerals and Rocks

• About one-third of 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.• Salt harvest

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.

• Sea animals may mistake trash for food and eat plastic that can block their digestive system. They also get tangled in and even strangled by plastic waste.

Pollution affects the ocean.

• Chemical pollutants, nuclear wastes, and heavy metals like mercury and lead can harm and kill ocean life.

• Pregnant women are sometimes advised not to eat tuna and other fish because it may contain low levels of toxic mercury, which could damage the developing child.

Pollution affects the ocean.

• Human waste, sewage, and fertilizers have caused dead zones in the ocean – areas where no plants or animals can live.

• These pollutants contain nutrients and cause a huge increase in the amount of algae that live in the area.

• When the algae die, bacteria consume them = large numbers of bacteria use up all the oxygen in an area of ocean = animals cannot survive.

Pollution affects the ocean.

• Although oil spills are dramatic events that kill many animals, they account for only a small percentage of the oil pollution in the ocean.

• More oil enters the ocean by washing off the land than by being spilled.

• In addition to oil, pesticides, fertilizers, and many other pollutants wash into the ocean from the land.

Preventing Ocean Pollution

• 1988 – U.S. restricts the use of a harmful chemical that had been used in ship paint = levels of that chemical dropped in certain areas of the ocean = the health of some types of sea life, such as oysters, improved

• Government organizations have also banned the dumping of some chemicals into the ocean = reduced some kinds of pollution

Preventing Ocean Pollution

• Many people may not realize that oil or other chemicals dumped in a drain or sewer or on the ground can end up in the ocean.

• The Environmental Protection Agency (EPA) has information about the proper disposal of many common chemicals. Go to www.epa.gov.

Global Pollution Problems

• Ocean currents circulate water around the globe and carry pollutants to all parts of the ocean.

• The United Nations, through its 1994 Law of the Sea, attempts to manage ocean resources and to conserve ocean environments.

• Calls on all countries to enforce pollution controls; sets pollution rules for ships in international waters; regulates fishing; attempts to divide rights to undersea resources