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Volume of Earth's Oceans

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Bibliographic Entry Result
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Garrison, Tom S. Oceanography: An Invitation to Marine Science. Thompson Brooks/Cole, 2005: 4. "The average depth of the ocean is about 3,796 meters (12,451 feet), the volume of seawater 1.37 billion cubic kilometers" 1.37
billion km3
"The World Ocean." The Columbia Encyclopedia. CD-ROM. 2007, 6th Ed. New York: Columbia University Press. "The World ocean has an area of about 361 million sq km (139,400,000 sq mi), an average depth of about 3,730 m (12,230) ft, and a total volume of about 1,347,000,000 cu km (322,280,000 cu mi)." 1.347
billion km3
Viau, Elizabeth Anne. World Builders: Water on Earth. California State University Los Angeles. 2003. [see table 1] 1.310302
billion km3
Gleick, P.H. Earth's water distribution. Water Science for Schools. U.S. Geological Survey. 28 August 2006. [see table 2] 1.338
billion km3
"Ocean Volume and Depth." Van Nostrand's Scientific Encyclopedia 10th ed. 2008. "The volume of the oceans and their seas is nearly 1.5 × 109 [sic] cubic kilometers" 1.5
billion km3

You've heard it all before: 70 percent of the earth is covered in water! But what does that really mean? These waters that are spoken of have a breakdown into five different categories: Oceans, rivers, lakes, groundwater, and ice. As an essential part of our daily diet, water is vital for the survival of our ecosystem. The world's oceans comprise 97.3% of the total water on earth and consists of 5 oceans: Atlantic, Pacific, Indian, Arctic, and Southern. The current range for the volume of the world's ocean is from 1.3 to 1.5 billion cubic kilometers and it will still get larger and larger as time passes.

There are two origins of water: comets (extraterrestrial bombardment) and out gassing (condensation of steam from early volcanism). These processes are continuing today. It is estimated that the volume of the earth's ocean increases by 1 cubic meter every year.

Table 1: Where the Fresh Water Is
  Volume in Thousands
of Cubic Kilometers
Percentage of
Total Water on Earth
Oceans 1,310,302 97.3 This is salty sea water. 
Ice 29,492 2.2 Much of this ice is in the Antarctic
Groundwater 6,733 0.5 Underground aquifers, deep wells
Lakes 242 0.02 Provide drinking water, irrigation water, fish and recreation
Soil Moisture 74 0.005 This is being used by our crops, trees, and surface vegetation
Water Vapor in the Atmosphere 14 0.001  Clouds, fog, and dew
Rivers 1.3 0.0001 Provide water for drinking, irrigation, and recreation
Adapted from: Environment Canada
Table 2: One estimate of global water distribution:
Water source Water volume,
in cubic miles
Water volume,
in cubic kilometers
Percent of
fresh water
Percent of
total water
Oceans, Seas, & Bays 321,000,000 1,338,000,000 -- 96.5
Ice caps, Glaciers, & Permanent Snow 5,773,000 24,064,000 68.7 1.74
Groundwater 5,614,000 23,400,000 -- 1.7
Fresh 2,526,000 10,530,000 30.1 0.76
Saline 3,088,000 12,870,000 -- 0.94
Soil Moisture 3,959 16,500 0.05 0.001
Ground Ice & Permafrost 71,970 300,000 0.86 0.022
Lakes 42,320 176,400 -- 0.013
Fresh 21,830 91,000 0.26 0.007
Saline 20,490 85,400 -- 0.006
Atmosphere 3,095 12,900 0.04 0.001
Swamp Water 2,752 11,470 0.03 0.0008
Rivers 509 2,120 0.006 0.0002
Biological Water 269 1,120 0.003 0.0001
Total 332,500,000 1,386,000,000 - 100
Source: Gleick, P. H., 1996: Water resources. In Encyclopedia of Climate and Weather, ed. by S. H. Schneider, Oxford University Press, New York, vol. 2, pp. 817-823.

Ketsia Erra -- 2008

Bibliographic Entry Result
(w/surrounding text)
Duxbury, Alyn. An Introduction to the World's Oceans - Sixth Edition. McGraw-Hill, 2000: 39. "The volume of water in the oceans is enormous: 1.37 billion cubic kilometers (1.37 × 109 km3, or 0.328 × 109 mi.3)" 1.37 × 109 km3
Ocean and Oceanography. Microsoft Encarta. "The world ocean covers 71 percent of the earth's surface, or about 361 million sq km (140 million sq mi). Its average depth is 5,000 m (16,000 ft), and its total volume is about 1,347,000,000 cu km (322,300,000 cu mi)." 1.347 × 109 km3
Kennish, Michael J. Practical Handbook of Marine Science - Second Edition. Boca Raton: CRC Press, 1994: 181. "Volume of Oceans without adjacent seas (106 km3) is 1,303.51 and Arctic Ocean is 13.70." 1.32 × 109 km3
Oceans and Seas. Infoplease.
sq. mi.sq. kmft.m
Pacific Ocean64,000,000165,760,00013,2154,028
Atlantic Ocean31,815,00082,400,00012,8803,926
Indian Ocean25,300,00065,526,70013,0023,963
Arctic Ocean5,440,20014,090,0003,9531,205
1.268 × 109 km3

We as humans don't realize the significance of water on earth. Its not just coincidence that nearly three-fourths of the Earth is covered with water. This amount is necessary for earth's natural processes to occur and therefore sustain life on Earth, not only for humans but also animals, plants and other organisms. If this isn't interesting enough then this might raise a few brows. If mined, all the gold suspended in the world's oceans and seas would give each person on earth 9 pounds.

The volume of the Earth's oceans is approximately 1.3 × 109 km3. The largest of the oceans is the Pacific Ocean followed by Atlantic, Indian and Arctic Ocean. Given their sheer volume, 99 percent of the living space on the planet is found in the oceans. If species are removed from the ecosystem, the web of relationships is disrupted. Whether most people realize it or not, humans are part of the world's ecosystems for our most basic needs, including food, medicines, pure water, and the even the air we breathe.

The average depth of the oceans is 2.5 miles (4 km). The deepest point lies in the Mariana Trench, 6.8 miles (10.9 km) down. By the way in comparison, Mount Everest is only 5.5 miles (8.8 km) high. Climbing up to Mt. Everest provides an extremely dangerous challenge, but try reaching the depths of the Mariana Trench where the pressure is extremely high and temperature very low. At the deepest point in the ocean the pressure is more than 8 tons per square inch, or the equivalent of one person trying to support 50 jumbo jets. At 4 °C (39 °F), the temperature of almost all of the deep ocean is only a few degrees above freezing.

The Earth is rather unique than all the other planets in our solar system. No other planet has liquid water and thus is one of the problems of not being able to live on Mars.

Syed S. Qadri -- 2001

Bibliographic Entry Result
(w/surrounding text)
Debenedetti, Pablo G. & H. Eugene Stanley. "Supercooled and Glassy Water." Physics Today. Vol. 56, No. 6 (June 2003): 40. "Water is not only fascinating, but it is also one of the most important and ubiquitous substances on Earth. There are 1.3 × 109 km3 of water in the oceans, 3.3 × 107 km3 in the polar ice caps, 2 × 105 km3 in glaciers, 105 km3 in lakes, and 1.2 × 103 km3 in rivers. In addition, 2.2 × 105 km3 of water fall annually as precipitation." 1.3 × 109 km3

Editor's Supplement -- 2003

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