The Antarctic Going to extremes. What is the Antarctic? The area south of the Antarctic circle and...

The Antarctic

Going to extremes

What is the Antarctic?

• The area south of the Antarctic circle and around the south pole.– Below latitude 66° 33′ 39″ south – Antarctic opposite to Arctic

Antarctic Circle

CIA World Fact book image

Antarctic circle

Which countries are closest to the Antarctic?

http://www.worldatlas.com/webimage/countrys/an.htm

Daylight in the Antarctic

At every point, 24 hours of continuous daylight as least once per year (midnight sun)– At every point, 24 hours of continuous darkness as

least once per year (polar night)– Additional all light / all dark days as you go further

south

• When is the shortest day in the year in your area?

• How long is it?

Antarctica• Continent extending to

the south pole, mostly inside the Antarctic circle

• 14.4 million square kilometers– 5.4 million square miles– 5th largest continent (larger

than Europe)– How does this area

compare with the lower 48 states in the US?

• Highest average elevation of all the continents

NASA composite photo

It’s a hard place to live• No bears• No indigenous

people• Penguins• Seals• Whales• Mosses• Lichens• Algae• Scientists• Whalers, in

earlier times

Emperor penguin chicks

Cape fur seal

Adelle Penguins

Humpback whalePhoto by M. Sternheim

Humpback whale

Photo by M. Sternheim

It is very cold and dry

• Colder than the Arctic– Higher elevation, often 3 km above sea level (much of

Antarctica is a high plateau)• Where in the US is the altitude this high or higher?• How high is it at your school?

– Arctic ocean warms the polar area somewhat– Lowest temperature ever recorded on earth, -89.2 ºC

• A frozen desert – dry as the Sahara• Driest of all the continents

– Less than 1 inch of annual precipitation in some areas– 4 inches at the south pole– What is the annual average in your area?

The south pole

• The average winter temperature at the south pole is -59 ºC

• Warmest summer temperature at the south pole on record is -14 ºC – What is the typical

temperature range in your area?

http://astro.uchicago.edu/cara/vtour/pole/poles/

Antarctica ice sheet

• 98% covered by ice, about 2100 meters (7000 feet) thick

• 90% of world’s ice, 70% of world’s fresh water

• If it all melted, sea level would rise ~61 meters (200 feet)– Not too likely, since the

average temperature is -37 ºC, and never above freezing most places

Warming and ice sheets

• Adjoining floating ice sheets might start to disintegrate with warming

• Icebergs could then break off the continental shelves

• Partially offset by increased snowfall with warming

• Perhaps eventual a few meter rise in sea levels

A mini-history of Antarctica

• 350 BC. Greeks invent idea to balance Arctic with opposite (anti) mass, Antarctic

• 1773. James Cook circumnavigates Antarctica

• 1819-1823. Whalers and sealers land

• 1840’s. French, British, Americans sail continuous coastline and establish Antarctica as a continent

Mini-history, cotd.• 1902. Captain Robert Scott, UK,

fails to reach the south pole with his team

• 1907. Ernest Shackelton, UK, comes closer and turns back

• 1911. Norwegian Roald Amundsen is first to reach the pole; his party dies on return

• 1929. First flight over south pole (Byrd, US)

• 1956. First flight lands at the south pole (US) – first humans at pole since 1911

• 1957. 60 research stations established, 12 nations

• 1961. Antarctic treaty signed assuring peaceful uses

4th International Polar Year (IPY)

• International effect to study physical, geological, and biological aspects of the polar regions

• March 2007 – March 2009• Antarctic research agenda

– Sediment and ice core drilling to trace climate change

– Subglacial lakes in Antarctica: liquid water under 3000 meters of ice!

Subglacial lakes

• High pressure and suitable temperatures make them possible– First suspected in 1950’s– Radar, seismic data show over 140 exist– Lake Vostok is as large as Lake Ontario

• Research agenda– To understand the formation and evolution of subglacial lake

processes and environments– To determine the origins, evolution and maintenance of life in

subglacial lake environments

• Challenge: How can you do this through 3000 m of ice and not disturb possible organisms or introduce new ones?

Antarctic Subglacial Lakes

Known subglacial lakes

http://salegos-scar.montana.edu/

Lake Vostok

Lake Vostok Largest subglacial lake