Antarctica

1
Antarctica

• Its cold here.

2

• Antarctica is the fifth largest of the seven
  continents.
• It is situated over the South Pole almost
  entirely south of latitude 6630' south (the
  Antarctic Circle).
• It is a very rough circular shape with the long
  arm of the Antarctic Peninsula stretching towards
  South America.
• There are two large indentations, the Ross and
  Weddell seas and their ice shelves.

3
Antarctica is a desert

• A Desert is defined as a region that has less
  than 254 mm (10 in) of annual rainfall or
  precipitation.
• In the interior of the continent the average
  annual precipitation (in equivalent of water) is
  only about 50 mm (about 2 in), less than the
  Sahara. 
• Along the coast, this increases, but is still
  only about 200 mm (8 in) in equivalent of water.
  Heavy snowfalls occur when cyclonic storms pick
  up moisture from the surrounding seas and then
  deposit this moisture as snow along the coasts.
• Unlike other deserts, there is little evaporation
  from Antarctica, so the relatively little snow
  that does fall, doesn't go away again. Instead it
  builds up over hundreds and thousands of years
  into enormously thick ice sheets.

4
Antarctica is the coldest and also the windiest
continent.

• The lowest temperature ever recorded anywhere on
  earth, -89.2 C (-128.6 F) was on July 21st 1983
  at the Russian base at the Southern Geomagnetic
  Pole.
• The continent is also buffeted by strong winds,
  calm periods are rare and typically last hours
  rather than days.
• A wind speed of 320 km/h (200 mph) was recorded
  at the French Dumont d'Urville base in July 
  1972.
• The winds  flow downwards from the interior
  toward the coast driven largely by gravity as air
  cools and becomes denser over the pole.

5
More than 99 percent of Antarctica is covered
with ice

• This contains about 70 percent of the world's
  fresh water.
• The thick ice cover makes it the highest of all
  continents, with an average elevation of about
  2300 m (about 7500 ft).
• The highest point on the continent is Vinson
  Massif 4897 m (about 16 066 feet) and the lowest
  point yet found is the Bentley Subglacial Trench
  (2499 m/8200 ft below sea level) in West
  Antarctica.

6
Antarctica has no trees or bushes at all

• Vegetation is limited to about 350 species of
  mostly lichens, mosses, and algae.
• In some places bare rocks are colonised by
  vibrant red, orange and yellow growths of
  lichens. Where rock is uncovered by ice for large
  parts of the summer, green lichens that grow to a
  few centimetres high
• In some places in the Antarctic continent such as
  in the dry valleys, rather than growing on rocks,
  some algae actually grow in the rock. Conditions
  are so harsh that it is easier to live in the
  rock despite low light levels, than it is exposed
  at the surface.

7
Animal life

• There are no land based vertebrate animals in
  Antarctica.
• All the vertebrates there are dependent on the
  sea for feeding or are migratory and leave the
  continent when the winter arrives.
• They are mainly warm blooded and tend to be
  pretty large as a survival technique against the
  extreme and relentless cold.
• That Antarctica can support such an abundance of
  large animals is a result of the productivity of
  the southern polar sea.

8
Krill are the engine that powers the Antarctic
ecosystem

• They are a small semi-transparent crustacean like
  a shrimp, about 4-5 cm (2") in length when fully
  grown,
• They can live for up to 6 years which is quite
  remarkable considering the wide variety of
  animals that feed on them in huge quantities.
• Krill belong to the animals that make up the
  zooplankton.

9
Elephant seals

• are the largest of all seals
• Males can grow to 4.5m long (15ft) and weigh up
  to 4 tonnes (8800lb).
• They are called elephant seals partly because of
  their size and also partly because of the males
  snout or trunk that he inflates to impress and
  intimidate rivals when competing with other
  males.
• Have a varied diet that they get from very deep
  dives, including shark, flatfish, ratfish, crab,
  squid, and octopus!

10
Crabeater seals

• Probably the most numerous large mammals on earth
  after humans. It is difficult to estimate their
  numbers, but by 2000 there were thought to be
  about 50 million.
• Crabeaters are large seals of about 220kg
  (484lb).
• Crabeater seals are uniquely adapted amongst
  seals in that their teeth are adapted to form a
  sieve in a similar manner to the baleen plates of
  the great whales.
• They take a mouthful of seawater and krill and
  expel the water through gaps in their teeth while
  the parts that overlap prevent the krill from
  escaping.
• Each seal consumes about 20kg of krill per day

11
Adélie penguins

• There are more Adélie penguins than any other
  penguin species.
• Average Weight 5kg - 11lb
• Adélie penguins are scared of Leopard seals (main
  predators of adult birds) and Skuas (prey on eggs
  and chicks on land).

12
Chinstrap penguins

• Called Chinstrap penguins because of their
  characteristic band of dark feathers under the
  chin that appears to be keeping their dark hats
  on
• They average about 4.5kg and 68cm tall.
• They are particularly noisy and aggressive

13
Killer Whales

• They toothed whales and while they are quite
  small compared to the great baleen whales
• They are at the very top of the Antarctic food
  chain due partly to their formidable array of
  teeth, but most of all due to the fact that they
  often hunt in packs or "pods".
• Their tastes are wide ranging from krill, squid,
  fish and sharks to penguins, seals and even the
  much larger baleen whales.
• They are found in almost all oceans, from the
  tropics to the Arctic and Antarctic where they
  will go deep into the pack-ice to hunt seals and
  penguins.
• They are commonest in coastal waters and in cool
  temperate and sub polar seas.

14
Sperm Whale

• Only males are found in Antarctic waters. The
  males being about one and a half times longer,
  but considerably heavier than the females
• Unusually, sperm whales only have teeth in their
  lower jaw, these fitting into depressions in the
  upper jaw.
• Sperm whales are found in all oceans and
  latitudes from the equator to the edge of the
  polar pack ice
• A whole range of cephalopods (squid, octopuses
  and cuttlefish), deep-sea fish, and non-food
  items have been found in the stomachs of sperm
  whales around the world.

15
Antarctic skua

• They nest all around continental Antarctica and
  breed into the deep south.
• They are excellent fliers and have occasionally
  been sighted deep in the interior hundreds of
  miles from anything other than ice.
• One of their feeding techniques is to chase and
  bully other birds into regurgitating the contents
  of their crop, a strategy successful with some
  species that are in themselves excellent fliers.
• Skuas eat krill, fish, and penguin eggs and chicks