OA - Antarctica Lesson

Antarctica

The Southern Ocean and Antarctica

Map of Antarctica and the South Ocean

 

The Southern Ocean

The Southern Ocean, which surrounds the continent of Antarctica, is often not included on many maps of the Southern Hemisphere. This may be since its northern boundary does not border a landmass. Instead, the Southern Ocean's northern boundary has more to do with the marine conditions than physical landmasses. Most geographers agree that the northern boundary of the Southern Ocean is south 60° latitude where it meets up with the Atlantic, Pacific, and Indian Oceans. This area is called the zone of Subtropical Convergence and can be visually observed due to the colors of the waters. The grayish, cold southern waters off the coast of Antarctica move from west to east in a clockwise rotation around the continent in a movement called the West Wind Drift, or the Antarctic Circumpolar Current. As the waters drift north and meet up with the bluish-green, warm northern waters of the Pacific, Atlantic, and Indian Oceans, they sink below the warm waters from the north and create a zone of upwelling. Fortunately, this mixing of water is conducive to elevated levels of productivity for organisms such as phytoplankton and krill. The krill, which thrive on phytoplankton, are an important link in the food chain for marine organisms such as fish, penguins, seals, albatrosses, and whales in the Southern Ocean.

Emperor Penguins, Ross Sea, Antarctica

Photo of an Emperor Penguin

Size and Elevation 

 Size Comparison of Antarctica and the United States

Size Comparison showing the US on top of Antartica. Rank of 7 Continents in Square Miles 1. Asia - 17,139,445 2. Africa - 11,677,239 3. North America - 9,361,791 4. South America - 6,880,706 5. Antarctica (with ice sheet) - 5,400,000 6. Europe (with Russian Region) - 3,997,929 7. Australia - 2,967,124 The United States (land area) - 3,537,438

Antarctica without the ice sheet would be smaller; some estimate it would be only about one hundred thousand square miles in land area, or the equivalent of the physical area of the US state of Colorado.

When rated by physical area from the largest to the smallest, the world's seven continents are Asia, Africa, North America, South America, Antarctica, Australia, and Europe. Antarctica, which is larger than Australia and Europe, is located entirely south of 60° latitude and has the highest average elevation of any continent. The continent's high elevation is the result of its mountain ranges: the Transantarctic Mountains and the Ellsworth Mountains. Dividing Antarctica into a small western region and a larger eastern region, is the two-thousand-mile-long Transantarctic Mountain range, which runs north-south and terminates into ice shelves. Nestled in the western region of Antarctica, the Ellsworth Mountains include the continent's highest mountain, Mt. Vinson (or the Vinson Massif). At an elevation of 16,050 feet, Mt. Vinson has a higher elevation than any mountain in the continental United States, Europe, or Australia. 

Ice Sheets

About 98 percent of Antarctica is covered by an ice sheet that is, on average, up to a mile deep. In some areas, it is three miles deep. In the winter season, the ice sheet's area might double as it extends out from the coastline to form an ice shelf. An ice shelf is a floating platform of ice that forms when a glacier or ice sheet flows out and onto ocean waters. The Antarctic ice sheet holds about 70 percent of the earth's fresh water and if they were to melt, the sea level could rise considerably. The threat of sea levels rising concerns many of the people living on the earth's islands, peninsulas, and coastal regions with low elevations.

Bare Ground

There are areas in Antarctica that are not covered with ice but have a landscape of bare ground. This iceless portion of the continent protrudes above the ice sheet and only covers a combined physical area equivalent to about half the US state of Kentucky. Many different mosses and lichens grow during short periods of the year and are the only plant life that exists.

Desert

Antarctica is considered a desert because it usually averages fewer than ten inches of precipitation per year. Coastal regions annually receive as much as four feet of snow, while the interior near the South Pole might only receive a few inches.

Photo of Mt Erebus - Mt. Erebus (12,448 feet), located on Ross Island, is Antarctica's most active volcano and has a lava lake in its inner crater.

Volcanic Activity

The Antarctic Peninsula is an extension of the Andes Mountains of South America. The peninsula is home to active volcanoes which include an underwater volcano discovered in 2004. There are volcanoes on the other side of Antarctica as well. Ross Island holds the distinction of having the world's southernmost active volcano, Mt. Erebus (12,448 feet). Active since 1972, Mt. Erebus has a large lava lake in its inner crater.

Lakes

Below the giant ice sheet are dozens of subglacial lakes. Lake Vostok, the largest lake discovered in the Antarctic so far, was found two miles below the ice sheet and is the size of Lake Ontario. It is unknown what aquatic life might exist in these subglacial lakes.

Climate

Not only is Antarctica the driest continent with the least average annual precipitation and the highest continent in average elevation; it is also the coldest of the continents. The lowest temperature ever recorded on Earth was −128°F in 1983 at a Russian research station in Antarctica. Temperatures reach a minimum of less than −110°F in winter in the interior and greater than 55°F near the coast in summer. No permanent human settlements exist in Antarctica other than research stations from several countries.

Complete the review activity.

 

Map Activity IconOceania and Antarctica Map Activity

Identify the following key places on a map:

Countries:

            • Australia
            • New Zealand

Melanesia:

Independent Countries of Melanesia

  • Fiji
  • Papua New Guinea
  • Solomon Islands
  • Vanuatu

Other Island Groups

  • New Caledonia (France)

Micronesia :

Independent Countries of Micronesia

  • Federated States of Micronesia
  • Kiribati (Western)
  • Marshall Islands
  • Nauru
  • Palau

Other Island Groups

  • Guam (US)
  • Gilbert Islands (Kiribati)
  • Northern Mariana Islands (US)
  • Wake Island (US)

Polynesia:

Independent Countries of Polynesia

  • Kiribati (eastern)
  • Samoa
  • Tonga
  • Tuvalu

Main Island Possessions

  • American Samoa (US)
  • Cook Islands (NZ)
  • Hawaiian Islands (US)
  • Pitcairn Islands (UK)
  • French Polynesia (FR)
    • Austral Islands, The Marquesas, Society Islands, Tahiti, and Tuamotu Islands

Other Physical Locations to locate:

Bodies of Water:

  • Atlantic Ocean
  • Indian Ocean
  • Pacific Ocean
  • Southern Ocean

Cities:

  • Darwin
  • Melbourne
  • Perth
  • Sidney

Mountains:

  • Mauna Kea
  • Mt. Erebus
  • Mt. Kilauea
  • Mt. Vinson

Rivers:

  • Darling-Murray River   * Be sure to track the flow of the river.

Antarctica:

  • Antarctic Peninsula
  • East Antarctica
  • Ellsworth Mountains
  • Lake Vostok
  • Ronne Ice Shelf
  • Ross Ice Shelf          
  • South Pole
  • Transantarctic Mountains

 

RESOURCES IN THIS MODULE ARE OPEN EDUCATIONAL RESOURCES (OER) OR CREATED BY GAVS UNLESS OTHERWISE NOTED. SOME IMAGES USED UNDER SUBSCRIPTION.