Chapter 24The Last Frontiers

“land of the midnight sun”◦ At least one 24 hr. period each year the sun never sets

Bounded by the Antarctic Circle at 66.5* latitude

Huge packs of permanent floating ice defied exploration

Icebergs- jagged chunks of ice broken off from glaciers

Technically, Antarctica is surrounded by 3 oceans (Pacific, Atlantic and Indian) , but a band of polar water circles the continent and is much colder and less salty◦ Some call the Southern Ocean a “fifth” ocean◦ Ice pack covers the polar water◦ Ice that breaks off: ice floes◦ Open water between the floes: lead

I. Antarctica

East Antarctica◦ High plateau covered by ice more than a mile

deep◦ Avg. temp in the interior during coldest months: -

94*F◦ Nothing lives in the interior, but due to

extreme cold no snow falls◦ On Ross Sea, McMurdo Station—largest

settlement in Antarctica. West Antarctica

◦ Ross Sea and Weddell Sea cut in on on either side Separated from South Pole by the Transantarctic

Mountains◦ Mountainous rather than flat

Highest mountains on continent: Ellsworth Mts. Solitary mountains called: nunataks

◦ Antarctic Peninsula- most coveted area, extends toward South America

Physical Geography

1773- Captain Cook circled Antarctica looking for the fabled southern continent, but couldn’t get through the ice

1820- American, Russian and English sealing ships each claim to be the first to sight Antarctica

1895- Norwegian man, Henryk Johan Bull, became the first to step foot on the land

1911- Roald Amundsen plants a Norwegian flag at the South Pole, at the same time British Robert Scott was struggling to reach the site—he did, but entire crew died on the way back

Exploration

Foreign powers began establishing bases in Antarctica in the 1940s

Scientists from around the world pleaded for the area to remain neutral and free to science

From 1957-1958, 12 nations worked together to set up 60 stations and agreed to share their findings◦ All signed the Antarctic Treaty- agreement to ban

military bases and weapons testing◦ In 1991, the treaty was renewed, more nations signed on

and it was termed “indefinite” in its time frame Fears: ozone hole above Antarctica

◦90% of Earth’s ice is locked up in ice caps◦ if ice caps were to melt seal level would rise

around the world, sinking many cities and islands

International Cooperation

Undersea Landscape◦ Features pg. 589◦ Continental Shelf- submerged edges of land◦ Continental Slope- edge of shelf, drops off sharply◦ Photic zone- enough light for photosynthesis, upper 700 feet of

the ocean, most of the fish we eat live here Midsea- mesopelagic- 2000 ft. deep Deep sea- bathypelagic- from mid sea down

◦ Ocean Basins- floor of ocean, stretched between continents◦ Abyssal Plains- flattest areas on earth, make up ½ the ocean

floor◦ Trenches- deep canyons, Pacific has the most, Mariana Trench is

the deepest (35,000 ft. deep)◦ Oceanic ridges- mountains that sometimes reach the surface to

create islands, Iceland is one such island◦ Seamounts-underwater volcanoes, new ones can form like

Surtsey◦ Deep sea vents- can spew hot lava or sulfur into the dark waters,

usually along fracture zones where earthquakes have happened

II. Ocean Deep

20th century explorers◦ First humans to go below the photic zone were

William Beebe and Otis Barton in 1930◦ Frenchman Jacques Cousteau invented the

Aqua-Lung in 1943 or self contained underwater breathing apparatus (SCUBA), made many explorations, filmed documentaries

◦ Robert Ballard- using a device named Argo discovered the wreckage of the Titanic in 1985

Exploration

During 17th century, nations declared 3-6 miles wide strip of water near coast to be Territorial Waters, beyond that was the High Seas –open to all

US supports the “freedom of the seas” idea today, but has become complicated as nations extend their territorial waters

UN recognizes 200 mile Exclusive Economic Zone (EEZ) for right to fish and drill for oil in the respective zone

Disputed Waters