Geography Reference
In-Depth Information
This is like the trick questions you got in high school from the “hard” teacher. In a sense, there are two
answers, both of them right. Strictly speaking, there is only one ocean, the great sheet of salt water that
altogether covers about 72 percent of the earth's surface and surrounds the planet's great land masses. But
in more familiar terms, the One Great Ocean is divided into four principal parts, each of them known as an
ocean.
The Pacific covers about 70 million square miles (181,300,000 square km) and is by far the largest
ocean, containing about 46 percent of the earth's water. Bounded by the Americas on the east and Asia
on its west, the Pacific is flanked by high mountain chains and is remarkable for its many small islands,
many of them volcanic. The Pacific is larger than all the land in the world put together. It extends almost
from pole to pole but is largely a tropical ocean, and half of the equator's length of 24,000 miles (38,500
km) lies within the Pacific. The Challenger Deep in the Mariana Trench, which extends from southeast of
Guam to northwest of the Mariana Islands in the Pacific Ocean, is the deepest place in the oceans of the
world, plunging to 36,198 feet (11,040 meters); if Mount Everest were dropped into the Mariana Trench,
it would not break the surface of the Pacific.
The Atlantic is the second largest ocean, containing about 23 percent of the world's water. Although its
extent from north to south is about the same as the Pacific's, it is much narrower and only half the size of
the Pacific, covering about 32 million square miles (82,217,000 square km). An S-shaped body bounded
by the Americas on the west and Europe and Africa on the east, it is not as deep as the Pacific and contains
many fewer islands. Lying between highly industrialized continents, the North Atlantic carries the greatest
proportion of the world's shipping. Although half of the world's fish are caught in the Atlantic, with much
of that catch coming from the Grand Banks, an underwater plateau off Newfoundland, pollution and over-
fishing by commercial fleets threaten the existence of a number of Atlantic fish species.
The Indian, called the Erythraean Sea in ancient times, is the third-largest ocean. Slightly smaller than
the Atlantic, it covers about 28 million square miles (73,426,500 square km), and holds 20 percent of the
world's water. Bounded by Asia to the north, Antarctica to the south, Africa to the west, and Australia and
Indonesia to the east, the Indian Ocean is divided in two by India, forming the Arabian Sea on one side and
the Bay of Bengal on the other. Ninety percent of the Indian Ocean lies south of the equator.
The Arctic, lying within the Arctic Circle and surrounding the North Pole, is the smallest ocean, with
an area of about 5.5 million square miles (13,986,000 square km) containing 4 percent of the world's wa-
ter. Connected to the Pacific by the Bering Strait (between Alaska and Russia) and to the Atlantic by the
Greenland Sea, the Arctic is frozen year-round except at its outer margins, but recent research suggests that
the Arctic is experiencing a period of warming.
Since 2000, the Great Southern, or Antarctic Ocean, which circles Antarctica, has been designated an
ocean by the International Hydrographic Organization, but as noted earlier, this extension of the southern
portions of the Pacific, Atlantic, and Indian Oceans is still not widely considered a fifth ocean.
Geographic Voices
Charles Darwin, from
The Voyage of the Beagle
(1839)
The day was glowing hot, and the scrambling over the rough surface and through the intricate
thickets, was very fatiguing; but I was well repaid by the strange Cyclopean scene. As I was walking
along I met two large tortoises, each of which must have weighed at least two hundred pounds: one
was eating a piece of cactus, and as I approached, it stared at me and slowly stalked away; the other
gave a deep hiss, and drew in its head. These huge reptiles, surrounded by the black lava, the leafless
shrubs, and large cacti, seemed to my fancy like some antediluvian animals. The few dull-colored
birds cared no more for me, than they did for the great tortoises.
On the 19th of August we finally left the shores of Brazil. I thank God, I shall never again visit
a slave-country. To this day, if I hear a distant scream, it recalls with painful vividness my feelings,
