Problem: Destruction of Coral Reefs
Coral reefs are important ocean habitats and offer a compelling case of the risks of climate change.
Reefs provide a large fraction of Earth’s biodiversity—they have been called “the rain forests of the
seas.” Scientists estimate that 25 percent of all marine species live in and around coral reefs, making
them one of the most diverse habitats in the world.
Paulo Maurin, education and fellowship coordinator for NOAA’s Coral Reef Conservation Program, says
the reefs are invaluable to our planet’s biodiversity.
“Corals are important to us for many reasons,” Maurin says. “From a practical point of view, they can
help protect coastlines from storm events, for instance, and help maintain fisheries that are essential to
a lot of people. And complex compounds found in coral reefs hold promises in modern medicine. These
are what we call ecosystem services that would be very difficult and expensive to replace.”
Reefs reflect the health of the ocean as a whole. Their growth patterns can provide a record of changes
in sea level. Reefs have also been found to be very sensitive to environmental changes. Increased water
temperature, as occurs in an El Niño, can cause the coral to bleach, or lose color. The reefs expel their
algae, weaken, and die. Marine organisms that depend on the reef either die or leave. Since the mid1980s, oceanographers have seen an alarming trend of coral bleaching. By 2007, 25% of the world's
coral reefs had died, and scientists predict that 60% may also die within 25 years.
Works Cited
"Coral Reef." Grolier Multimedia Encyclopedia. Grolier Online, 2014. Web. 5 Jan. 2014.
Richardson, L. Jeremy, and Stuart Thornton. "Coral Reefs." National Geographic Education. National
Geographic, 1 Nov. 2011. Web. 06 Jan. 2014.
Problem: Oil Spills
An oil spill is the release of oil into the environment. Oil spills in the ocean usually happen when an
ocean oil rig (machines used to mine oil from the ocean) springs a leak or when an ocean going tanker
(carrying oil) wrecks. Several large oil spills have resulted from these two means, such as the Santa
Barbara spill in 1969, and the Exxon Valdez spill in Alaska in 1989. The most recent oil spill happened in
April 2010 when a broken BP oil rig spewed about 5 billion barrels of crude oil into the Gulf of Mexico.
Oil spills can cause lasting harm to plants, animals, and other living things. They are often difficult and
expensive to clean up. Oil is a liquid form of petroleum. It forms deep underground. Most oil is less
dense than water. Thus, oil typically floats on water. But floating oil soon breaks up. The oil may sink
underwater. Waves and currents can also carry the oil far away from the spill.
Birds, turtles, fish, and many other animals can become coated with spilled oil. They usually die as a
result. Oil can also kill plants and poison animals nearby. A recent study of the dolphins in the Gulf of
Mexico following the 2010 BP oil spill showed that they suffered from lung disease as a result of the
spill.
People clean up oil spills in a number of ways. Floating barriers called booms can block the spread of oil.
Materials called sorbents "soak up" the oil like sponges. Skimmers and nets can also recover oil.
Chemicals called dispersants push oil into deeper waters. Microbes (tiny living things) can also help
break up oil. But no single method works perfectly to clean up oil.
Works Cited
Anderson, Genny. "Human's Impact on the Oceans." Marine Science. Genny Anderson, 19 Aug. 2006.
Web. 05 Jan. 2014.
"Oil spill." WorldBook Kids.World Book, 2014. Web. 5 Jan. 2014
Than, Ker. "Dolphin Illnesses Linked to Gulf Oil Spill." National Geographic. National Geographic Society,
20 Dec. 2013. Web. 03 Jan. 2014.
Problem: Endangered Dolphins
Dolphins and porpoises are members of the most playful and intelligent group of animals living in the
sea. They have been known since ancient times for their frolicsome habits around boats and human
divers. Their ability to be trained easily and to carry out complex behaviors has made them popular
attractions at many ocean aquariums.
The single threat to the world's dolphin population—and it is a serious one—comes from tuna fishing.
Because schools of the yellowfin tuna often swim underneath schools of dolphins, the fishing nets are
set around both. When the nets are pulled in, the dolphins are captured along with the tuna, and they
drown. Hundreds of thousands of dolphins have been killed in this way. But the Marine Mammal
Protection Act, passed by the U.S. Congress in 1972, restricts the number of dolphins that U.S. fishing
fleets can kill yearly. New nets have been designed with a type of "gateway" at the top that permits the
dolphins to escape while the tuna remain inside. In addition, a tuna boycott led major U.S. tuna
companies to agree in 1990 to catch only tuna that swim separately from dolphins, further protecting
these animals.
Works Cited
Wood, F. G., Jr. "Dolphins and Porpoises." The New Book of Knowledge. Grolier Online, 2014. Web. 5
Jan. 2014.
Problem: Sharks are disappearing
Most people think of sharks as vicious killing machines. It is true that some sharks are among the
ocean's fiercest predators. But usually sharks have more to fear from people than people have to fear
from sharks.
There are about 400 species of sharks, divided into about 30 families. They are found in all the world's
oceans except the Antarctic. Some species live in shallow waters. Other species prefer the deep ocean.
Some species enter fresh waters occasionally. The smallest shark is the pale catshark. It grows to only
about 8 inches (20 centimeters) long. The largest shark is the whale shark. This gentle giant can reach
more than 60 feet (18.3 meters) in length.
As the top predators in marine environments, sharks help maintain the balance in the food chain of their
ecosystems. But human activities such as fishing are placing increasing pressure on these species—many
sharks are caught in the nets of ships whose target is other fish. Sharks replace their populations very
slowly. Thus overfishing can happen quickly. Populations of some shark species are so low that they are
considered commercially extinct. Some species of sharks are legally protected. Monitoring these
populations is essential to help maintain the role of sharks in the careful balance of nature.
It is estimated that more than 70 million sharks are killed every year. Recent evidence shows a
worldwide decrease in the populations of many sharks. Their absence has allowed ray and skate
populations to increase; these in turn have destroyed scallop beds. Researchers warn that some shark
species may disappear if present fishing levels remain unrestricted.
Works Cited
Gilbert, Claire K., and Perry W. Gilbert. "Shark." Grolier Multimedia Encyclopedia. Grolier Online, 2014.
Web. 5 Jan. 2014.
Long, Douglas J. "Shark." The New Book of Knowledge. Grolier Online, 2014. Web. 5 Jan. 2014.
Problem: Endangered Sea Turtles
Sea turtles are large turtles that live almost their whole lives in the ocean. They hatch from eggs laid on
land, but immediately enter the water. They can travel thousands of miles or kilometers across the seas.
Their large flippers make them excellent swimmers. However, they are awkward on land, dragging
themselves along with their flippers. There are several kinds of sea turtles.
Female sea turtles return to land only to lay eggs. They usually return to the beaches where they were
born, even after traveling across the ocean. Newly hatched turtles scramble to the ocean to avoid being
eaten by birds and other animals. Most male sea turtles never come onto land again.
Most sea turtles eat algae and sea grasses. They also eat such animals as crabs, fish, and shrimp. Some
kinds of sea turtles have more specialized diets. For example, sea turtles called leatherbacks eat jellyfish.
There were once hundreds of millions of sea turtles. Their numbers have plunged because of human
activities. People hunt sea turtles for their meat and eggs. Many sea turtles die after becoming trapped
in large nets of commercial fishing boats. Oil spills and litter pollute the oceans and harm sea turtles.
Beach development can harm sea turtle nesting sites. Many turtles have also died after eating plastic
garbage apparently mistaken for jellyfish, their favorite food.
Works Cited
Campbell, Jonathan. "Leatherback Turtle." Grolier Multimedia Encyclopedia. Grolier Online, 2014. Web.
5 Jan. 2014.
“Sea turtle." WorldBook Kids.World Book, 2014. Web. 5 Jan. 2014.
Problem: Endangered Manatees
Manatees are sometimes called sea cows. However, despite their massive bulk, they are graceful
swimmers in coastal waters and rivers. Powering themselves with their strong tails, manatees typically
glide along at 5 miles (8 kilometers) an hour but can swim 15 miles (24 kilometers) an hour in short
bursts.
Manatees are usually seen alone, in pairs, or in small groups of a half dozen or fewer animals. From
above the water's surface, the animal's nose and nostrils are often the only thing visible. Manatees
never leave the water but, like all marine mammals, they must breathe air at the surface. A resting
manatee can remain submerged for up to 15 minutes, but while swimming, it must surface every three
or four minutes.
There are three species of manatee, distinguished primarily by where they live. One manatee population
ranges along the North American east coast from Florida to Brazil. Other species inhabit the Amazon
River and the west coast and rivers of Africa.
Manatees are large, slow-moving animals that frequent coastal waters and rivers. These attributes make
them vulnerable to hunters seeking their hides, oil, and bones. Manatee numbers declined throughout
the last century, mostly because of hunting pressure. Today, manatees are endangered. Though
protected by laws, they still face threats. The gentle beasts are often accidentally hit by motorboats in
ever more crowded waters, and sometimes become entangled in fishing nets.
Works Cited
"Manatee." National Geographic. National Geographic Society, 2014. Web. 05 Jan. 2014.
Problem: Rising Sea Levels
Scientists tell us that by 2100, sea levels will rise several feet, flooding wetlands, beaches and coastal
cities. And higher water levels will worsen any damage from storm surges or extreme high tides.
What's making sea levels rise? There are two main causes. First, when a liquid is heated, it occupies
more space. So as our oceans warm due to climate change, they'll begin to expand and sea levels will
rise.
Second, glacial ice is melting. When floating sea ice melts, it doesn't add to the volume in the ocean, just
as a melting ice cube won't raise the level in your drink. But in places where glacial ice covers the
ground, meltwater flows off the land and into the sea. And when water is added to the ocean in this
way, sea levels rise.
Works Cited
"Changing Seas." Monterey Bay Aquarium. Monterery Bay Aquarium Foundation, 2014. Web. 06 Jan.
2014.
Problem: The Rising Ocean Temperature
Warming water temperatures affect ocean animals in different ways, and animals that can adapt will be
the ones to survive.
What's causing warmer seas? Carbon dioxide and other greenhouse gases are trapping heat near the
Earth's surface warming the land and the seas. (Most of these gases come from burning fossil fuels like
gas and coal for energy.) Even small temperature changes can have big effects. Scientists warn that the
Arctic's summer sea ice could vanish much sooner than we think—as early as 2013.
Also, thermal pollution happens because the ocean is used as a cooling agent - the cool ocean water
taken in is released at a higher temperature. Although the temperature of release is usually controlled
by laws, and is not such a threat as the other forms of pollution mentioned here, one could imagine
what it would be like if more and more plants began using ocean water as a coolant. This change in
temperature, due to humans in this case, would change the makeup of the species in these areas.
In Monterey Bay, California, warmer seas are giving porcelain crabs heart attacks—water that's too
warm stresses the crabs. But researchers at the Monterey Bay Aquarium Research Institute tell us that
the change in temperature might be good news for some deep-sea jellies, whose populations have
increased in the past 20 years.
Warmer ocean waters are also killing some corals, leaving only bleached-white coral skeletons. They can
come back, but slowly. Bleached reefs are more common now—and more vulnerable to other ocean
changes.
Works Cited
Anderson, Genny. "Human's Impact on the Oceans." Marine Science. Genny Anderson, 19 Aug. 2006.
Web. 05 Jan. 2014.
"Changing Seas." Monterey Bay Aquarium. Monterey Bay Aquarium Foundation, 2014. Web. 06 Jan.
2014.
Problem: Oceans Becoming Acidic
Warmer ocean waters and changing ocean chemistry are harming coral reefs and preventing some
animals from forming shells.
What's going on here? Corals build rocky skeletons from calcium and carbonate, chemicals found
naturally in the ocean. But when oceans become more acidic, acid soaks up the loose carbonate. With
less of that critical building block, it's much harder for corals to form a reef.
More acidic oceans may also affect tiny, free-swimming shelled animals—called pteropods or "sea
butterflies." If pteropods disappear, animals that rely on them—everything from small schooling fishes
to commercially important species like Pacific salmon—will be affected in ways no one can predict.
Can corals, pteropods and other sea life survive? Maybe, if we give them time to adjust. Animals must
adapt to this new ocean chemistry, and that'll be easier for some than for others. If we slow down ocean
changes now, we can give ocean species a chance to survive.
Works Cited
"Changing Seas." Monterey Bay Aquarium. Monterey Bay Aquarium Foundation, 2014. Web. 06 Jan.
2014.
Problem: Garbage in the Ocean
Trash is one of man's most widespread pollutants. Beaches all over the world become littered with the
trash produced by mankind - much of which is disposed of at sea and then floats all over the world in
the currents. Remember that all oceans of the world interconnect so anything put in one ocean could
conceivably end up anywhere on Earth, and it does.
The Great Pacific Trash Patch (also called the Eastern Pacific Garbage Patch and the Pacific Trach Vortex)
is a slowly rotating mass of trash-filled water about twice the size of Texas.
"It moves around like a big animal without a leash," said Curtis Ebbesmeyer, an oceanographer in Seattle
and leading expert on currents and marine debris. "When it gets close to an island, the garbage patch
barfs, and you get a beach covered with this confetti of plastic."
The amount of material in the Great Pacific Garbage Patch accumulates because much of it is not
biodegradable. Many plastics, for instance, do not wear down; they simply break into tinier and tinier
pieces.
Nearly 90% of floating marine litter is plastic — supple, durable materials such as polyethylene and
polypropylene, Styrofoam, nylon and saran. An estimated 1 million seabirds choke or get tangled in
plastic nets or other debris every year. About 100,000 seals, sea lions, whales, dolphins, other marine
mammals and sea turtles suffer the same fate.
Works Cited
"Great Pacific Garbage Patch." National Geographic Education. National Geographic Society, 2014. Web.
05 Jan. 2014.
Weiss, Kenneth. "Plague of Plastic Chokes the Seas." Los Angeles Times. Los Angeles Times, 02 Aug.
2006. Web. 07 Jan. 2014.
Problem: Overfishing
Ocean overfishing is simply the taking of wildlife from the sea at rates too high for fished species to
replace themselves. The earliest overfishing occurred in the early 1800s when humans, seeking blubber
for lamp oil, decimated the whale population. Some fish that we eat, including Atlantic cod and herring
and California's sardines, were also harvested to the brink of extinction by the mid-1900s.
In the mid-20th century, international efforts to increase the availability and affordability of protein-rich
foods led to government efforts to increase fishing capacity. However, in 2003, a scientific report
estimated that industrial fishing had reduced the number of large ocean fish to just 10 percent of their
population.
Faced with the collapse of large-fish populations, commercial fleets are going deeper in the ocean and
father down the food chain for viable catches. This so-called "fishing down" is triggering a chain reaction
that is upsetting the ancient and delicate balance of the sea's biologic system.
A study of catch data published in 2006 in the journal Science grimly predicted that if fishing rates
continue apace, all the world's fisheries will have collapsed by the year 2048.
Works Cited
"The Ocean: Overfishing." National Geographic. National Geographic Society, 2014. Web. 05 Jan. 2014.
Problem: Invasive Species
An invasive, or non-native, aquatic species can be any organism that exists somewhere in or near water
where it doesn't belong. When an alien species like this arrives in a new location, several things can
happen: It can find its new habitat unwelcoming and die off; it can survive with little environmental
impact; or it can take over, harming the naturally existing wildlife in a variety of ways.
Invasive species that thrive usually do so because their new habitat lacks natural predators to control
their population. They do damage mainly by consuming native species, competing with them for food or
space, or introducing disease.
Introduction of alien species is usually caused by our shipping industry. Ships, traveling worldwide, pick
up marine species both on the hulls of their ships and in ballast water. As they travel the globe, these
species can be introduced to new areas. Probably most of these species die because the environment is
not right for them but a few survive and may out-compete the native species, leaving an unbalanced
ecosystem. In California the Chinese mitten crab (Eriocheir) is an example of a recent introduction that is
out-competing the native species and causing problems.
One infamous example is the zebra mussel, accidentally introduced by a cargo ship into the North
American Great Lakes from the Black Sea in 1988. The tiny mollusk multiplied uncontrollably, starving
out many of the Great Lakes' native mussel populations and interfering with human structures from
factory intake pipes to ship rudders. They've now spread from Canada to Mexico and are considered a
major nuisance species. Hundreds of millions of dollars are spent annually to control their numbers.
Works Cited
Anderson, Genny. "Human's Impact on the Oceans." Marine Science. Genny Anderson, 19 Aug. 2006.
Web. 05 Jan. 2014.
"The Ocean: Marine Invasive Species." National Geographic. National Geographic Society, 2014. Web. 07
Jan. 2014.
Problem: Endangered Right Whales
Right whales are the rarest of all large whales. There are several species, but all are identified by
enormous heads, which can measure up to one-third of their total body length. These whales' massive
heads and jaws accommodate hundreds of baleen "teeth." Rights and other baleen-feeding whales use
a comblike strainer of baleen plates and bristles to ensnare tiny morsels of food as they swim. Right
whales feed on zooplankton and other tiny organisms using baleens up to 8 feet (2.4 meters) long.
Right whales were named by whalers who identified them as the "right" whale to kill on a hunt. These
leviathans had enormous value for their plentiful oil and baleen, which were used for corsets, buggy
whips, and other contrivances. Because of their thick blubber, right whales also float accommodatingly
after they have been killed. Populations of these whales were decimated during the whaling heydays of
the 17th, 18th, and 19th centuries. During this period they came close to extinction.
Today, right whales are threatened by the fishing and shipping industries. Whales either get caught in
fishing nets or are hit by ships that travel through their habitats.
Northern right whales are the most endangered of all large whales. They number only several hundred,
and populations do not appear to have grown in the decades since their protection began.
Works Cited
"North Atlantic Right Whales." Florida Fish and Wildlife Conservation Commission. State of Florida, 2014.
Web. 07 Jan. 2014.
"Right Whale." National Geographic. National Geographic Society, 2014. Web. 07 Jan. 2014.