5 Oceans

The largest and deepest of World Oceans is the Pacific Ocean. It extends from the Arctic Ocean to the Antarctic and is bounded by Asia and Australia. At 63.8 million square miles, it covers about 46% of Earth’s hydrosphere making it larger than all of Earth’s land area. Pacific ocean detaches Asia and Australia from the Americas. The average depth is 4,280 m (14,040 ft) and the maximum is Marianas Trench which goes deep to 10,911 m (35,797 ft).

The Pacific Ocean, as most of the world’s oceans, was formed millions of years ago with unique topography. Because of its large size, it plays an important role in weather patterns around the globe.

Pacific Ocean History

There is no identifiable time when the Pacific Ocean was developed this is because the ocean floor continuously recycles itself as it moves. The latest claims are that the oldest known Pacific Ocean floor is about 180 million years old.

Human migrations have occurred in the Pacific in prehistoric times. Austronesian people in Taiwan practiced long-distance canoe travel. They spread themselves and their languages to the Philippines, Indonesia, and Southeast Asia.

Famous explorer, Ferdinand Magellan named this ocean as the Pacific Ocean in 1520. It was called “pacific” (adj. peaceful) due to the calmness of the water at the time.

Geography

Pacific ocean lies between Asia and Australia in the west, the Americas in the east, the Southern Ocean to the South, and the Arctic Ocean to the north. The area surrounding the Pacific Ocean is often called the Pacific Ring of Fire. This region has the world’s largest area of volcanism and earthquakes.

Water Characteristics

Temperatures in the Pacific Ocean vary from freezing in the poleward areas to about 25 to 30° C. Its salinity also varies by latitude. The nearer the water is by the equator, the less salty it is compared to those found in the mid-latitudes. That is due to the profuse equatorial precipitation throughout the year.

Climate

As it was to the salinity, climate also relies greatly on latitude along with the presence of landmasses and types of air moving around or over its waters. Sea surface temperatures play a vital role because it affects the availability of moisture in various regions. The climate is tropical, wet, and warm throughout most of the year near the equator. Far north Pacific and South Pacific are milder and have greater seasonal variances in weather patterns.

Geology

The Pacific Ocean is exposed to geological activities such as volcanism and earthquakes since their seafloors sit above subduction zones where the rims of the Earth are pressed down against others after a collision. Hotspot volcanic activities also happen in some areas where magma is forced up from the Earth’s mantle through the crust creating underwater volcanoes that eventually form island and seamounts.

Economy

As the Pacific Ocean covers 28% of the world’s surface, it is home to diverse fish, plants, and other animals. It plays a major role in the world economy because it provides easy access to ship goods from Asia to North America and vice versa. The fishing industry is also happening to the large portion of the Pacific Ocean. It is also a rich source of natural resources, including oil and other minerals.

The Five Oceans

The Blue Planet is how the Earth is best described. With the abundance of water, it looks beautifully blue from outer space. No other planet in this universe has the same amount of water as that of the Earth. It is what makes our world unique to other planets. The ocean is from Ancient Greek  Ὠκεανός or Okeanos – believed by the ancient Greeks and Romans to be the divine personification of the sea, an enormous river encircling the world. The ocean is every so often interchanged with “sea” in American English. By definition, the sea is a body of saline water (within the world ocean division) partly enclosed by land. “The Sea” also refers to the ocean.

The Earth’s hydrosphere is made up mostly of oceans but it also embodies other bodies of water like lakes, seas, rivers, and underground waters.

Names of the five oceans

Oceans are Earth’s major conventional divisions. By order, they are; Pacific, Atlantic, Indian, Southern (Antarctic), and Arctic Oceans. These bodies of water contain 97% of Earth’s water and less than 5% of it has been explored. Its total volume is approximately 1.35 billion cubic kilometers and an average depth of closely 3,700 meters.

Oceans, being the world’s principal component is integral to life. It shapes part of the carbon cycle and has a great impact on climate and weather patterns. It is the habitat of more or less 230,000 known species, however, since much of it remains unexplored, the number of species that exist in the ocean may be much larger – perhaps over a couple billion. The origin of Earth’s ocean is yet completely understood. There are several compatible hypotheses as to how these bodies accumulated Earth.

The five oceans, although generally described as separate bodies of water are still interconnected body of salt. Listed down in descending order by area and volume are the major oceanic divisions.

Sources: Encyclopedia of Earth,[19][20][21][22][26] International Hydrographic Organization,[23] Regional Oceanography: an Introduction (Tomczak, 2005),[24] Encyclopædia Britannica,[25] and the International Telecommunication Union.

Physical Properties

Less than 3% of the Earth’s hydrosphere is freshwater. The rest is salt water almost all of which is in the ocean. The world ocean is about 139.7 million square miles and covers nearly 70.9% of the Earth’s surface. Its volume is approximately 323.3 million cubic miles.

The ocean, as huge as it is does not have a constant temperature. Energy is imparted from sunlight throughout all summer, the ocean holds it in so that once winter comes, it can release the warmth back into the atmosphere according to their heat capacity. Its density as with other sea waters is nearly uniform at all latitudes. Surface density lessens a little by the equator which is a phenomenon due to tropical climates. Pycnocline is the sharp difference in density within the tropical regions.

Water’s bluish color is a fuse of a number of contributing agents. Dissolved organic matter and chlorophyll are prominent factors. Oceanographers and seafarers have claimed that the ocean emits an evident glow which extends for miles at night. This glow, as announced by scientists is most likely caused by bioluminescence.

Exploration

The deepest point amongst all the oceans is the Marianas Trench, located in the Pacific Ocean. Only 5% of the total water surface has been explored and much remains to be learned from it. SONAR or Sound Navigation and Ranging is the technology that is very effective for studying and mapping the ocean. This technology uses sound waves to develop nautical charts and to check for underwater hazards.

Biology

Water Cycle plays a vital role in marine biology. Oceanic evaporation is the starting place of most rainfall. Ocean temperatures also establish climate and wind patterns that affect life on land and underwater. Life has evolved underwater earlier than it did on land. The diversity of life underwater is immense that it includes the smallest to the biggest creature there is – from bacteria (single-celled prokaryotes), archaea, algae (including organisms like Pyropia – or the edible Nori seaweed), plants (including seagrasses and mangroves), fungi, and animals. Most animal Phyla have species that inhabit the ocean such as sponges, corals, jellyfish, crustaceans, etc., Land animals have also tailored their living to the oceans, like seabirds, penguins, seagulls, and pelicans.

Salinity

The Earth’s oceans have a salinity of about 3.5 percent or 35 parts per thousand. It means that for every liter of ocean water, there are 35 grams of salt dissolved in it. Halocline is the zone of rapid salinity increase with depth. When salt content increases, the temperature of maximum sea water density decreases. Salinity also affects ocean temperature whereas the freezing temperature of water decreases with salinity and boiling temperature of water increases with salinity. Many chemicals in the oceans make it salty. These chemicals get there from rivers carrying chemicals dissolved from rock and soil. Leading is sodium chloride or often just called salt.

Salinity also varies with the location. There are portions of the ocean where it hardly rains but constantly getting warm dry winds causing too much evaporation. Evaporation removes water and when water vapor rises, it leaves the salt behind thus, causing the salinity of the saltwater to increase on that point. Increased salinity causes water to become denser. The Mediterranean Sea in Europe has a very high salinity as there is more evaporation than there is rain.

Those parts of ocean that get lots of rain get freshwater added and dilutes seawater. As it does, it reduces salinity and makes the ocean less dense. The ocean around Antarctica has a low salinity due do thawed icebergs that add freshwater. The ice sheets that broke off that formed over land do not contain salt.

Economic Value

According to the WWF, our oceans are worth at least $24 trillion. Goods and services are done from and within coastal and marine environments amount to around $2.5 trillion each year. More than two-thirds of the oceans’ economic values rely on healthy condition. If there is too much habitat destruction, overfishing, pollution, and climate change, it imperils this economic engine and the livelihoods it supports.

Antarctic Ocean – Comprising the southernmost waters of the World Ocean is the Antarctic Ocean, also known as the Southern Ocean or Austral Ocean. It is the fourth largest of the 5 oceans. This is where cold, northward flowing waters from the Antarctic mix with warmer subantarctic waters.

This ocean extends from the coast of Antarctica north to 60° S. For some time, the only oceans recognized by geographic circles were Arctic, Atlantic, Indian, and Pacific. However, the IHO (International Hydrographic Organization) settled this debate through a 2000 publication that affirmed, named and defined the Antarctic Ocean. Limits of Oceans and Seas (S-23), published the names and locations of seas and oceans. Its third edition in 2000 confirmed the existence of the Antarctic Ocean as the 5^th world ocean.

Antarctic Ocean

Geography

This Ocean lies approximately 7.8 million square miles and about the double the size of USA. Its lowest point is 23,737 feet below sea level in the South Sandwich Trench.

Waters of this Ocean differs from the waters in other oceans making it a reason to consider it as a separate ocean. Its waters get carried around fairly rapidly due to Antarctic Circumpolar Current which circulates around Antarctica.

Climate

The Antarctic Ocean often experiences cyclone like storms and it results from the stark contrast in the middle of the ice packs and ocean waves. They are very harsh for any sailors or marine vessels that happen to be caught in their path.

Water surface temperatures vary from -2° to 10° C. In winter, the ocean freezes away to 65° S in Pacific and 55° S in the Atlantic sector. This lowers surface temperatures well below 0°C. Continual intense drainage at some coastal points, however, keep the shoreline ice-free throughout the year.

Biodiversity

Marine animals present in Antarctic Ocean rely directly and indirectly on phytoplankton. Sealife like penguins, blue whales, orcas, colossal squids, and fur seals can be found here. There are also a few fish species existent. Most species found are snailfish, cod ice fish, and eelpout. They account for almost 9/10 of the nearly 320 described fish species in Antarctic Ocean. Birds can be found on the rocky shores of mainland Antarctica. It provides nesting space for over 100 million birds every spring. This includes albatrosses, petrels, skuas, gulls, and terns. Flightless penguins are located in Southern Hemisphere while 4 of the other penguin species live on the mainland and its close offshore islands.

Economy

Producing more or less 119,898 tons in 1998 alone, fisheries are the largest amount of exports in the Antarctic Ocean. This industry relies on open entry to ports along the which, during the winters months are unfortunately limited because of ice build-up.

Environmental Issues

Antarctic Ocean confronts distinct ecological hazards to its natural marine ecosystems. The first is the constant ultraviolet radiation that courses into the ocean from the Antarctic ozone hole causing the productivity of phytoplankton to reduce. Illegal and unreported fishing moreover affects the sustainability of stocks. International agreements regarding the world’s oceans include the and are subject-specific to this region. Some of which are; International Whaling Commission, Convention for the Conservation of Antarctic Seals, and Convention of the Conservation of Antarctic Marine Living Resources. Antarctic Treaty protects the division of the globe 60°S thus, claims to Antarctica and all islands surrounding are suspended.

The Atlantic Ocean – With an area of about 41.1 million square miles, the Atlantic Ocean, the world’s second largest ocean covers approximately 20% of the Earth’s surface and about 29% of its water surface area. This separates the Old World (Africa, Asia, and Europe) from the New World (the majority of Western Hemisphere, specifically the Americas).

Named after the god of Atlas from Greek mythology, its name means “seas of Atlas.”

The Atlantic is S-shaped and narrow in relation to length. It isn’t the largest of the world’s oceans but, it has by far the largest drainage area. By drainage it means, both sides of the Atlantic tend to slope towards it that it receives the waters of great proportion from the major rivers of the world.

Atlantic Ocean

Geography

Bounded on the west by North and South Africa, Atlantic Ocean also connects to the Arctic Ocean through Denmark Strait, Norwegian Sea, Greenland Sea, and the Barents Sea. The Mediterranean Sea also connects with it through Strait of Gibraltar. The 20° East Meridian defines the border between the Atlantic and the Indian Ocean.

Present in the Atlantic is natural hazards like that of icebergs located in Davis Strait, Denmark Strait, and Northwestern Atlantic. Thick fogs and icing in extreme northern locations and hurricanes that post threat from months of May to December.

Ocean Floor

The Mid Atlantic Ridge is an immense median mountain range extending all over the length of the Atlantic it the exceptional feature of the Atlantic Floor. It claims the center third of the ocean bed attaining almost 1,000 miles in extent. The large unstable island arcs were formed by the Lesser Antilles and the South Sandwich Islands. These arcs are found in steep-sided narrow gashes that drop to more than 7600 meters below sea level and more than 10,000 feet below the floors of adjacent basins.

Bordering Countries and Territories

This is the list of countries, states, and territories with a coastline on the Atlantic Ocean;

Ocean Water Characteristics

Latitude, current systems, and seasons that reflect the latitudinal distribution of solar energy affects the Atlantic Ocean’s surface water temperatures. North of the equator gets maximum temperatures and minimal values are being come across by the polar regions. Salinity values differ from one area of the Atlantic Ocean to another. North Atlantic is at its highest at 35.5 parts per thousand while lowest at Southern Atlantic at 34.5. The variance is the effect of the intense evaporation in the Mediterranean and the outflow from the sea.

Climate

As that of the salinity values of the Atlantic Ocean, its weather is different from North and South too. North Atlantic is greatly determined by wind currents and air masses coming from North America. South Atlantic however, is the belt of prevailing westerlies.

Terrain and Natural Resources

From North to South, there’s a relatively broad area of continental shelf that has given the Atlantic Ocean a proliferation of plants and animal species. There are a large variety of seaweeds, algae of commercial value, and large communities of crustaceans and fishes.

The Atlantic has also been used as oceanic highways to transport goods and passengers. The first records of extensive trading linkages are from Egyptian, Greek, Phoenician and Roman Civilizations dating far back 1500AD.

Indian Ocean – Covering 27.2 million square miles or approximately 20% of the water on Earth’s surface is the third largest ocean. This body of saltwater is bordered by Asia to the north, Australia and the Pacific Ocean to the east, the Southern Ocean to the south, and Africa and the Atlantic Ocean to the west. It is geologically youngest and physically the most complex of the world’s oceans. Part of this ocean is the Bay of Bengal, the Arabian Sea, the Persian Gulf, and the Red Sea. It expanses for more than 6,200 miles between southern tips of Africa and Australia.

Indian Ocean

Geography

The International Hydrographic Organization delineated the borders of the Indian Sea in 1953. It included the Southern Ocean but not the marginal seas by the northern rim. Outlining the oceanic limits of the Indian Ocean remains complicated and uncertain. The most agreed upon is that with the Atlantic Ocean, that flows from Cape Agulhas to south along the 20° E meridian to the shores of Antarctica. The Pacific Ocean to the southeast is frequently drawn from South East Cape by the Island of Tasmania south 147°E meridian to Antarctica. The northeastern margin is the most complicated to identify. The one settled upon runs northwest Cape Londonderry in Australia across the Timor Sea, by the southern shores of Lesser Sunda Islands and of Java, then Sunda Strait to the Island of Sumatra.

Rugged and seismically active mountain chain that is part of the worldwide oceanic ridge system is what the Indian Oceans ridges consist of. It forms an inverted Y on the ocean floor, from the upper northwest of Carlsberg Ridge in the Arabian Sea turning south past the Chagos-Laccadive Plateau and converting the mid-Indian Ridge. There are seamounts that are extinct submarine volcanoes that are conically shaped and flat-topped. Indian Ocean’s basins are characterized by even and flat plains of dense sediment with abyssal hills.

Bordering Countries and Territories

Climate

There are four general latitudinal climatic zones dependent on atmospheric circulation; monsoon, trade winds, subtropical and temperate, and subantarctic and Antarctic. The first zone, Monsoon Zone extends north from latitude 10° S, has monsoon climate described as semiannual reversing winds. Trade wind zone lies in the middle of 10° and 30° S. Its steady southeasterly trade winds exist throughout the year and the strongest are by months of June and September. The third zone sits in the subtropical and temperate latitudes of Southern hemisphere, between 30° to 45° S where prevailing winds are light and variable. The Subantarctic and Antarctic zone dominates the wide belt latitude 45° S and the continent of Antarctica. Constant westerly winds prevail which reaches gale forces at times with their passage through Antarctic low-pressure zones.

Hydrology

Indian Ocean’s hydrological characteristics are resultant from the interaction of atmospheric conditions with the surface, sources of water, deep circulation, all of which combine to shape generally horizontal layers of water. Wind drives ocean surface circulations. In monsoon zone, surface circulation reverses every half year and features opposing gyres that are separated by the Indian subcontinent.

Trade

For more than two millennia, the lateen-rigged sailing ferries called dhows were predominant in shipping within the Indian Ocean. This trade was most important in the western Indian Ocean, where they could take advantage of the monsoon winds. Shipping in the Indian Ocean are divided into three types; dhow, dry-cargo carriers, and tankers.

Marine and other Resources

The most valuable resource is Petroleum as the Persian Gulf is the largest oil-producing region in the world. Large reserves are believed to lie by the Arabian Sea and Bay of Bengal. Indian Ocean’s greatest part lies within the tropical and temperate zones. Its shallow waters have numerous corals and other organisms efficient of building together with calcareous red algae – reef and coral islands. The phenomenon wherein the upwellings that occur in coastal parts of the Indian Ocean, most especially in the Northern Arabian Sea along the South African coast and cause nutrients to concentrate on the surface of waters, produce immense quantities of phytoplankton. This phytoplankton are the basis of large inhabitants of commercially valuable marine animals.