The Atlantic Ocean
is the second-largest of the
divisions. With a total
of about 106.4 million square kilometres
(41.1 million square miles), it covers approximately one-fifth of
's surface and about one-quarter of
its water surface area. The first part of its name refers to the
of Greek mythology
, making the Atlantic the
"Sea of Atlas". The oldest known mention of this name is contained
in The Histories
around 450 BCE (I 202); see
also: Atlas Mountains
name historically used was the ancient term Ethiopic Ocean, derived from Ethiopia, whose name
was sometimes used as a synonym for all of
Africa and thus for the ocean.
Before Europeans discovered
other oceans, the term "ocean" itself was to them synonymous with
the waters beyond Western Europe that we now know as the Atlantic
and which the Greeks had believed to be a gigantic river encircling
the world; see Oceanus
The Atlantic Ocean occupies an elongated, S-shaped basin
extendinglongitudinally between the Americas
to the west, and Eurasia
component of the all-encompassing World
Ocean, it is connected in the north to the Arctic Ocean (which is sometimes considered a sea of the
Atlantic), to the Pacific
Ocean in the southwest, the Indian Ocean in the southeast, and the Southern Ocean in the south. (Alternatively, in
lieu of it connecting to the Southern Ocean, the Atlantic may be
reckoned to extend southward to Antarctica.) The equator subdivides it
into the North Atlantic Ocean and South
The Atlantic Ocean as seen from the
western coast of Portugal
The Atlantic Ocean is bounded on the west by North and South
America. It connects to the Arctic Ocean through the
Sea, and Barents
Sea. To the east, the boundaries of the ocean
proper are Europe, the Strait of
Gibraltar (where it connects with the Mediterranean
Sea, one of its marginal
seas, and, in turn, the Black Sea), and Africa.
In the southeast, the Atlantic
merges into the Indian Ocean. The 20° East
meridian, running south from Cape Agulhas to Antarctica defines its border. Some authorities show
it extending south to Antarctica, while others show it bounded at the 60° parallel by the Southern
Ocean. In the southwest, the Drake Passage connects it to the Pacific Ocean.
man-made Panama Canal links the Atlantic and Pacific. Besides those
mentioned, other large bodies of water adjacent to the Atlantic are
Sea, the Gulf of Mexico, Hudson
Bay, the Arctic Ocean, the Mediterranean Sea, the
Sea, the Baltic
Sea, and the Celtic Sea.
Covering approximately 22% of Earth's surface, the Atlantic is
second in size to the Pacific. With its adjacent seas it occupies
an area of about ; without them, it has an area of . The land that
drains into the Atlantic covers four times that of either the
Pacific or Indian oceans. The volume of the Atlantic with its
adjacent seas is 354,700,000 cubic kilometers
(85,100,000 cu mi
) and without them
323,600,000 cubic kilometres (77,640,000 cu mi).
The average depth of the Atlantic, with its adjacent seas, is ;
without them it is . The greatest depth, , is in the Puerto Rico
Trench. The Atlantic's width varies from between
Brazil and Sierra Leone to over in the south.
major role in the expansion of Western civilization into the
Americas. Today, it can be referred to in a humorously diminutive
way as the Pond
in idioms, in reference to the
geographical and cultural divide between North America and Europe.
Some British people refer to the USA as "across the pond".
Map that uses color to show ocean
The principal feature of the bathymetry
) is a submarine
mountain range called the Mid-Atlantic Ridge
. It extends from
Iceland in the north to approximately 58° South latitude,
reaching a maximum width of about .
A great rift valley
also extends along the ridge over
most of its length. The depth of water over the ridge is less than
in most places, and several mountain peaks rise above the water and
form islands. The South Atlantic Ocean has an additional submarine
ridge, the Walvis Ridge
The Mid-Atlantic Ridge separates the Atlantic Ocean into two large
with depths from .
Transverse ridges running between the continents and the
Mid-Atlantic Ridge divide the ocean floor into numerous basins.
the larger basins are the Blake, Guiana,
North American, Cape Verde, and Canaries basins in the North
The largest South Atlantic basins are the Angola,
Cape, Argentina, and Brazil basins.
The deep ocean floor is thought to be fairly flat, although
numerous seamounts and some guyots
Several deeps or trenches are also found on the ocean floor.
Trench, in the North Atlantic, is the deepest at .
Laurentian Abyss is found off the
eastern coast of Canada.
South Sandwich Trench reaches
a depth of .
A third major trench
, is located near the
and reaches a depth of about . The
shelves along the margins of the continents constitute about 11% of
the bottom topography. Several deep channels cut across the
are composed of terrigenous
, pelagic, and authigenic
material. Terrigenous deposits consist
of sand, mud, and rock particles formed by erosion, weathering, and
volcanic activity on land and then washed to sea. These materials
are found mostly on the continental
and are thickest near large river mouths or off desert
coasts. Pelagic deposits, which contain the remains of organisms
that sink to the ocean floor, include red clays and Globigerina
and siliceous oozes. Covering most of the ocean floor and ranging
in thickness from they are thickest in the convergence belts and in
upwelling zones. Authigenic deposits consist of such materials as
. They occur where
sedimentation proceeds slowly or where currents sort the
Map of the five major ocean
On average, the Atlantic is the saltiest major ocean; surface water
in the open ocean ranges from 33
to 37 parts per thousand (3.3 - 3.7%) by mass and varies with
latitude and season. Evaporation, precipitation, river inflow and
melting influence surface salinity
values. Although the salinity values are just north of the equator
(because of heavy tropical rainfall), in general the lowest values
are in the high latitudes and along coasts where large rivers
enter. Maximum salinity values occur at about 25° north and south,
regions with low rainfall
and high evaporation.
Surface water temperatures, which vary with latitude, current
systems, and season and reflect the latitudinal distribution of
solar energy, range from below . Maximum temperatures occur north
of the equator, and minimum values are found in the polar regions.
In the middle latitudes, the area of maximum temperature
variations, values may vary by .
The Atlantic Ocean consists of four major water masses. The North
and South Atlantic central waters make up the surface. The
sub-Antarctic intermediate water extends to depths of . The
North Atlantic Deep Water
reaches depths of as much as . The Antarctic Bottom Water
basins at depths greater than 4,000 meters.
the North Atlantic, ocean currents isolate the Sargasso Sea, a large elongated body of water, with above
The Sargasso Sea contains large amounts of
and is also the spawning ground for
both the European eel
and the American eel
The Coriolis effect
Atlantic water in a clockwise direction, whereas South Atlantic
water circulates counter-clockwise. The south tides
in the Atlantic Ocean are semi-diurnal; that is,
two high tides occur during each 24 lunar hours. In latitudes above
40° North some east-west oscillation occurs.
Climate is influenced by the temperatures of the surface waters and
water currents as well as winds. Because of the ocean's great heat
retention capacity, maritime climates are more moderate and have
less extreme seasonal variations than inland climates. Precipitation
approximated from coastal weather data and air temperature from
water temperatures. The oceans are the major source of the
atmospheric moisture that is obtained through evaporation. Climatic
zones vary with latitude; the warmest zones stretch across the
Atlantic north of the equator. The coldest zones are in high
latitudes, with the coldest regions corresponding to the areas
covered by sea ice. Ocean currents influence climate by
transporting warm and cold waters to other regions. The winds that
are cooled or warmed when blowing over these currents influence
adjacent land areas. The Gulf Stream
and its northern extension towards Europe, the North Atlantic Drift, for example,
warms the atmosphere of the British Isles and north-western Europe,
and the cold water currents contribute to heavy fog off the coast
of eastern Canada (the Grand Banks of Newfoundland area) and Africa's north-western coast.
general, winds transport moisture and air over land areas. Hurricanes
develop in the southern part of
the North Atlantic Ocean.
The Atlantic Ocean appears to be the second youngest of the five
oceans. Apparently it did not exist prior to 130 million years ago,
when the continents that formed from the breakup of the ancestral
super continent, Pangaea
, were drifting
apart from seafloor spreading. The Atlantic has been extensively
explored since the earliest settlements along its shores.
Vikings, the Portuguese, and Christopher
Columbus were the most famous among early explorers.
After Columbus, European exploration rapidly accelerated, and many
new trade routes were established. As a result, the Atlantic became
and remains the major artery between Europe and the Americas
(known as transatlantic
explorations include the Challenger expedition, the German
Meteor expedition, Columbia
University's Lamont-Doherty Earth
Observatory and the United States
- In 1000, the Icelander, Leif
Ericson was the first European to discover North America's
Atlantic coast, including Vinland.
Norse discovery was documented in the 13th
century Icelandic Sagas and was
corroborated by recent archeological evidence.
- In 1003, Thorfinnr Karlsefni
led an attempted Viking settlement in North
America but was driven off by the natives.
- In 1004, Snorri Thorfinnsson
was the first European born on the American continent.
1419 and 1427, Portuguese
navigators reached Madeira and Azores,
1415 to 1488, Portuguese navigators sailed along the Western
African coast, reaching the Cape of Good Hope.
1492, Christopher Columbus
landed somewhere in The
- From 1499 to 1502, Amerigo
Vespucci mapped South America's east coast, proving that the
Americas are not Asia's east edge.
1500, Pedro Álvares Cabral
1524, Italian explorer Giovanni
da Verrazzano discovered the United States of America east coast.
- In 1764 William Harrison (the son of John Harrison) sailed aboard the HMS Tartar, with the H-4 time piece. The voyage became the
basis for the invention of the global system of Longitude.
- In 1858, Cyrus West Field laid
the first transatlantic
telegraph cable (it quickly failed).
- In 1865 Brunel's ship
the SS Great Eastern laid
the first successful transatlantic telegraph cable .
April 15, 1912 the RMS
Titanic sank after hitting an iceberg with a loss of more than 1,500
- 1914-1918, the First
Battle of the Atlantic took place.
- In 1919, the American NC-4 became the first
fixed-wing aircraft (seaplane)
to cross the Atlantic (though it made a couple of landings on
islands and the sea along the way, and taxied several hundred
in 1919, a British aeroplane piloted by
Alcock and Brown made the first
non-stop transatlantic flight, from Newfoundland to Ireland.
1921, the British were the first to cross the North Atlantic in an
- In 1922, Sacadura
Cabral and Gago Coutinho were the
first to cross the South Atlantic in an airship.
- The first transatlantic telephone call
was made on January 7, 1927.
1927, Charles Lindbergh made the
first solo non-stop transatlantic flight in an aircraft (between
City and Paris).
- In 1932, Amelia Earhart became the first female to make a solo
flight across the Atlantic
- 1939-1945, the Second
Battle of the Atlantic. Nearly 3,700 Allied ships were sunk at
a cost of 783 German U-boats.
- In 1952, Ann Davison was the first
woman to single-handedly sail the Atlantic
- In 1980, Gérard
d'Aboville was the first man to cross the Atlantic Ocean
1994, Guy Delage was the first man to
allegedly swim across the Atlantic Ocean (with the help of a kick
board, from Cape
Verde to Barbados.)
- In 1998, Benoît Lecomte was
the first man to swim across the northern Atlantic Ocean without a
kick board, stopping for only one week in the Azores.
1999, after rowing for 81 days and 4,767 kilometres
(2,962 mi), Tori Murden became the
first woman to cross the Atlantic Ocean by rowboat alone when she reached Guadeloupe from the Canary Islands.
Ethiopic Ocean or Ethiopian Ocean
(Okeanos Aithiopos) is an old name for what is now called the South
Atlantic Ocean, which is separated from the North Atlantic Ocean by
a narrow region between Natal, Brazil and Monrovia, Liberia.
Use of this term illustrates a past trend
towards referring to the whole continent of Africa
by the name Aethiopia
. The modern nation of Ethiopia,
Africa, is nowhere near the Ethiopic
Ocean, which would be said to lie off the west
coast of Africa. The term Ethiopian Ocean
appeared until the mid-19th century.
The Atlantic has contributed significantly to the development and
economy of surrounding countries. Besides major transatlantic
transportation and communication routes, the Atlantic offers
deposits in the
continental shelves. The Atlantic hosts the world's richest
resources, especially in the waters
covering the shelves. The major fish are cod
, and mackerel
productive areas include Newfoundland's Grand
Banks, the Nova
Scotia shelf , Georges Bank off Cape
Cod, the Bahama
Banks, the waters around Iceland, the Irish Sea, the Dogger
Bank of the North Sea, and the Falkland Banks.
appear in great quantities. Because
environmental threats from oil spills, marine debris
, and the incineration
of toxic wastes at sea, various
international treaties attempt to reduce pollution.
October to June the surface is usually covered with sea ice in the
Strait, and Baltic
A clockwise warm-water gyre
occupies the northern Atlantic, and a
counter-clockwise warm-water gyre appears in the southern Atlantic.
The Mid-Atlantic Ridge
, a rugged
north-south centerline for the entire Atlantic basin, first
discovered by the Challenger
dominates the ocean floor. This was formed by the
vulcanism that also formed the ocean floor and the islands rising
The Atlantic has irregular coasts indented by numerous bays, gulfs,
and seas. These include the Norwegian Sea, Baltic
Sea, Gulf of Saint Lawrence, Bay of
Fundy, Gulf of
Maine, Mediterranean Sea, Gulf of
Mexico, and Caribbean Sea.
include Greenland, Iceland, Faroe
Britain (including numerous surrounding islands), Ireland, Rockall, Newfoundland, Sable
Island, Azores, Madeira, Bermuda, Canary
Islands, Caribbean, Cape
Verde, São Tomé and Príncipe, Annobón Province, St. Peter
Island, Fernando de Noronha, Rocas
Island, Saint Helena, The Islands
of Trindad, Tristan
da Cunha, Gough
Island (Also known as Diego Alvarez), Falkland
del Fuego, South Georgia
Island, South Sandwich
Islands, and Bouvet
The Atlantic harbors petroleum
, marine mammals
and whales), sand
, and precious stones.
Icebergs are common from February to August in the
Strait, and the northwestern Atlantic and have been
spotted as far south as Bermuda and Madeira.
Iceberg A22A in the South Atlantic
Ships are subject to superstructure icing
in the extreme north from October to
May. Persistent fog can be a maritime hazard from May to September,
as can hurricanes north of the equator (May to December).
The United States' southeast coast has a long history of shipwrecks
due to its many shoals and reefs. The Virginia and North Carolina
coasts were particularly dangerous.
Triangle is popularly believed to be the site of numerous
aviation and shipping incidents because of unexplained and
supposedly mysterious causes, but Coast
Guard records do not support this belief.
Current environmental issues
Endangered marine species include the manatee
, sea lions
. Drift net
fishing can kill dolphins
and other seabirds (petrels
), hastening the fish
stock decline and contributing to international disputes.
pollution comes from the eastern United States, southern Brazil, and eastern
Argentina; oil pollution in the Caribbean Sea, Gulf of
Maracaibo, Mediterranean Sea, and North
Sea; and industrial waste and municipal sewage
pollution in the Baltic
Sea, and Mediterranean Sea.
In 2005, there was some concern that warm northern European
currents were slowing down, but no scientific consensus formed from
On June 7, 2006, Florida's wildlife commission voted to take the
manatee off the state's endangered species list. Some
environmentalists worry that this could erode safeguards for the
popular sea creature.
Marine pollution is a generic term for the entry into the ocean of
potentially hazardous chemicals or particles. The biggest culprits
are rivers and with them many agriculture fertilizer
chemicals as well as livestock
The excess of oxygen-depleting chemicals leads to hypoxia
and the creation of a
, also known as marine
litter, describes human-created waste floating in a body of water.
Oceanic debris tends to accumulate at the center of gyres and
coastlines, frequently washing aground where it is known as beach
Major ports and harbours
- Limits of Oceans and Seas.
International Hydrographic Organization Special Publication No. 23,
- Example: BBC Click - Episode 04 April 2009
- "Introduction" U-Boat Operations of the Second World
War—Vol 1 by Wynn, Kenneth, 1998 p. 1
- animallaw.info: Problems and Prospects for the
- Atlantic Ocean's 'Heat Engine' Chills Down by
Christopher Joyce. All Things Considered, National Public Radio, 30
- Gerlach: Marine Pollution, Springer, Berlin (1975)
Much of this article comes from the public domain site
http://oceanographer.navy.mil/atlantic.html (dead link
). It is now accessible from the Internet
- Disclaimers for this website, including its status as a public
domain resource, are recorded on the Internet Archive at