Antarctica Flashcards
Where is most of Antarctica located?
South of the Antarctic Circle
What is most of the continent’s coastline fringed by?
Ice shelves
Name the two largest ice sheets in Antarctica
The Ross Ice Shelf and the Ronne Ice Shelf
Where is the Ross Ice Shelf located?
In the Ross Sea
Where is the Ronne Ice Shelf located?
In the Weddell Sea
How big are the Ross and Ronne ice shelves?
They each cover an area greater than the British Isles
What happened in the spring of 2000?
The International Hydrographic Organization delimited a fifth world ocean
What is the fifth world ocean called?
The Southern Ocean/ Antarctic Ocean
What does the Southern Ocean comprise of?
The southernmost waters of the world, taken as being south of 60degrees S latitude
What does the Southern Ocean have the unique distinction of?
It is a large circumpolar body of water totally encircling the continent of Antarctica
How many degrees of longitude does the Southern Ocean encompass?
360 degrees of longitude
Where does the Southern Ocean extend to?
From the east coast of Antarctica north to 60 degrees south latitude
What coincides with the Antarctic Treaty Limit?
The boundary of the Southern Ocean
What happens at 60 degrees south latitude?
The cold northward flowing waters from the Antarctic meet with warmer sub-Antarctic waters
What is the Antarctic Convergence zone?
The place where the cold northward flowing waters meet the warmer sub-Antarctic waters
How wide is the Antarctic Convergence zone?
32-48km wide
Why does the Antarctic Convergence zone vary in latitude and longitude?
It changes in latitude due to seasonal changes
What happens to the waters in the Antarctic Convergence zone?
The cold, northward flowing Antarctic waters sink beneath the sub-Antarctic waters
Where does upwelling occur?
In the Antarctic Convergence
What are upwelling currrents high in?
Marine productivity
What is often found in the Antarctic Convergence?
Antarctic krill
Is the Antarctic Convergence a natural boundary or an artificial one?
Natural
What three things does the Antarctic Convergence separate?
Two distinct hydrological regions
Areas of distinct climate
Areas of distinctive wildlife
What is the largest surface current in the world?
The Antarctic Circumpolar Current
Where is the Antarctic Circumpolar Current?
60 degrees latitude south at the Convergence Zone
What does the Antarctic Circumpolar Current do?
Blocks warmer waters travelling southwards
Where does the Antarctic Circumpolar Current travel?
It flows in an eastwards direction around Antarctica
What drives the Antarctic Circumpolar Current?
Westerly winds
What is the Antarctic Circumpolar Current also known as?
The West Wind Drift
What is the East Wind Drift?
A lesser current that flows in the opposite direction to the Antarctic Circumpolar Current
Where does the East Wind Drift feature prominently?
In the Ross and Weddell Seas
What is the Antarctic Divergence?
The area where East Wind Drift and the West Wind Drift meet.
What percentage of the continent is covered by glacial ice?
97%
What divides the continent?
The Transantarctic Mountains
How is the continent divided?
East (Greater) Antarctica and West (Lesser) Antarctica
How high are some of the peaks on the Transantarctic Mountains?
4000m
What else do the Transantarctic Mountains separate?
The larger, thicker and older East Antarctic Ice Sheet and the smaller, thinner and younger West Antarctic Ice Sheet
Where are the Ellsworth Mountains located?
In West Antarctica
What do the Ellsworth Mountains contain?
The continent’s highest peak
What is the continent’s highest peak?
Mount Vinson
How high is Mount Vinson?
4892m
What is the average height above sea level for Antarctica? How does it compare for other continents?
2,300m
Antarctica is the highest continent
What is the average temperature for Antarctica?
-49 degrees C
What can temperatures be as low as?
-89 degrees C
What is the mean annual wind speed?
50mph
What do the high wind speeds result from?
The convergent katabatic winds
What can gales reach?
Up to 200mph
What is the mean annual precipitation?
Less than 50mm per annum
Where is precipitation the lowest?
In the interior
What type of desert is Antarctica described as?
A polar desert
What are the thick ice sheets a result of?
The accumulation of small inputs of snow and frost over a very long period of time
Is heavy snowfall responsible for the thick ice sheets?
No
What is faster: the rate of ablation or the rate of accumulation?
The rate of accumulation is faster than the rate of ablation in Antarctica
What do ice-free areas owe their existence to?
Specific local scale factors
What are nunataks?
Small areas of rock emerging above the ice sheets
Why are the tops of nunataks not covered in snow and ice?
High winds and steep slopes prevent snow and ice accumulating on these parts of the mountains
Where are dry valleys found?
In high altitude areas of extreme aridity
What is higher: the surrounding sea temperatures or the land temperature?
The surrounding seas have higher temperatures than the continent itself
What does upwelling support?
Phytoplankton
What do blooms of phytoplankton provide?
Food for krill
Which species do other species depend upon to survive?
Krill
What do micro-climatic and topographic conditions mean for some coastal areas?
They cause enough melting in the summer months to allow some land to remain free of glaciers
Why are the areas on the western Peninsula likely to see more climatic differences as a result to climate change?
The melting in summer means that some land can be free of glaciers
When did sealing begin?
In the 18th century
Why were the seals culled?
For their fur
Where were the seals culled?
On and around the island of South Georgia
What had happened to the seal population of South Georgia by 1800?
They were wiped out
After sealing in South Georgia could no longer take place, where did people turn their interest to?
The South Shetland Islands
What happened within 3 years of sealing on the South Shetland Islands?
Over 300,000 seals had been killed and the population virtually eradicated
When did whaling begin?
The 19th century
What were the main targets for whaling?
blue and right whales
What were the main whaling products?
Oil and whalebone
Later on: meat meal, bonemeal, meat extract and even frozen whale meat
Which countries were mainly responsible for whaling in the Southern Ocean?
Norway, the USA and the UK
Where were whaling stations established?
On South Georgia and the South Shetlands
What did the Norwegians develop in 1904?
Grytviken (a whaling station)
At its height of success, how many people did Grytviken employ?
Over 300 people
When was Grytviken abandoned?
1965
Why was Grytviken abandoned?
Whale stocks were becoming seriously depleted and whaling was no longer commercially viable
What happened to the whale populations as a result of whaling?
They dramatically declined and some species became endangered
When was the International Whaling Commission (IWC) established?
1946
`When did the IWC end most whaling?
1985
What did the IWC do in 1994?
It established the Southern Ocean Whale Sanctuary
How big is the Southern Ocean Whale Sanctuary?
50 million square kilometers
What does the Southern Ocean Whale Sanctuary surround?
Antarctica
What is banned in the Southern Ocean Whale Sanctuary?
All types of commercial whaling
Who opposed the Southern Ocean Whale Sanctuary?
Japan
Who forms the main pro-whaling lobby?
Japan, Norway and Iceland
How often is the status of the Southern Ocean Whale Sanctuary reviewed?
Every 10 years
Why can Japan still hunt whales inside the sanctuary?
For scientific research purposes
What has Japan’s position on whaling meant for global governance?
International tensions on the issue
What has now replaced whaling?
Fishing
When did Fishing begin?
In the 1960s
Who started fishing first?
Russia
Give one species that is caught in Antarctica
Antarctic rock cod
Which countries seem to be fishing for a lot of krill and are causing concerns?
Japan and Russia
How much can someone expect to pay for 100 red krill oil capsules?
£40
What are krill a good source of?
Protein
In which area are krill sold as a source of protein?
East Asia
What is a problem with ships in Antarctica?
Ships dump waste into the ocean which contaminates the water and kills organisms.
What is happening to the sea ice on the eastern side of Antarctica?
It is increasing dramatically
What is happening to the land ice on the western side of Antarctica?
It is increasing but not as much as the sea ice on this side of the continent
What is happening to the land ice on the western side of the continent?
It is being significantly lost
What is happening to the sea ice on the western side of Antarctica?
It is not gaining anymore sea ice
What air temperature increase in the past 50 years has the Antarctic Peninsula experienced?
A 3 degrees C temperature rise which is a faster rate than the average for global warming
Why has the West Antarctic Ice Sheet thinned significantly?
The temperature of Western Antarctica has risen
What temperature increase has the Southern Ocean to the west of the Antarctic Peninsula experienced?
A 1 degrees C rise since 1955
What are the effects of the Antarctic Circumpolar Current warming?
The distribution of penguin colonies has changed
Melting of snow and ice cover has increased colonisation by plants
Decline in the abundance of Antarctic krill
Glaciers and ice shelves fringing the Peninsula have either retreated or collapsed entirely
Melting ice shelves increases the flow of the glaciers behind them- these glaciers melt causing sea levels to rise
What was the extent of the Antarctic sea ice in 2013?
20 million square km which is bigger than the continental land mass itself
How thick is sea ice?
1-2m
How is sea ice formed?
It forms when water is cooled sufficiently by the surrounding atmosphere
What happens when sea ice is formed?
It is blown by wind or moved by currents, ultimately expanding and bonding with other floating sheets of ice.
What are the 4 reasons why climate change may contribute to Antarctic sea ice expansion?
Increasing westerly winds around the Southern Ocean, caused by climate change and ozone depletion are driving the seas northwards
More rain and snow are layering the Southern Ocean with a cooler, denser layer on top
Storms freshen the water and therefore raising the temperature for sea ice to form
Increased melting of continental land ice creates more floating icebergs which contribute to sea ice formation
What makes the ocean becomes slightly less alkaline?
Carbonic acid from CO2 emissions
What has been projected for polar and sub-polar marine ecosystems?
They are projected to become so low in carbonate ions within this century that waters may actually become corrosive to unprotected shells and skeletons of organisms currently living there
Why has there never been any commercial mining in Antarctica?
Mining is completely banned by the Antarctic Treaty
Will the decision made by the Antarctic Treaty to ban mining be changed?
No
What could the demand for resources in the future mean for Antarctica?
Pressure will be put on the vast mineral reserves that are to be found on the continent
Why is it not currently economically viable to mine in Antarctica?
Any sizeable deposits that are easy to reach are rare and currently not economically viable to mine
Why are the minerals so inaccessible?
Due to the vast coverings of moving ice streams and glaciers
What were some members of the Antarctic Treaty secretly trying to do in the 1970s and 1980s?
They were trying to formulate a new minerals convention which would have allowed exploration and possible future exploitation of mineral and gas reserves
When was the Mineral Convention adopted?
1988
Why did the Mineral Convention never come into force?
It was not ratified by all members
What are the two main human threats to Antarctica?
Scientists and tourists
What are the impacts of humans inhabiting Antarctica?
Vehicle exhausts, construction of buildings and related facilities such as fuel storage, runways and the disposal of waste such as rope, fuel drums and plastics (all of which endangers living organisms)
What are the 3 types of Antarctic tourism?
Camping trips
Ship-board visits
Over-flights
Who are the camping trips for?
Naturalists, photographers and journalists
How do the ship-board visits work?
Cruise ships or converted Russian ice breakers
Why did over-flights stop?
A New Zealand aeroplane crashed into Mount Erebus, killing all passengers
When were over-flights resumed?
20 years following the plane crash
What do tourists go to Antarctica to see?
Glacial landscapes and wildlife. They also go for the isolation and the chance to tests themselves in adverse weather conditions
What historic sites can tourists see?
The McMurdo Sound with its huts dating from the Scott and Shakleton expeditions
When does tourism take place?
In the short southern summer period
When is the short southern summer period?
Mid-November to March
What does ship-borne tourism in Antarctica take the form of?
Expeditions
When did the first tourist ship arrive?
1958
What is the capacity of most of the tourist ships?
50-100 people
What are tourists briefed about?
Code of conduct, adherence to health and safety requirements and rules about wildlife observation
What plan do most cruises follow?
The Lindblad Plan
What does the Lindblad Plan manage?
It manages itineraries in a way that any effects are negligible
How does the Lindblad Plan work?
There are 200 possible sites to visit.
Groups of 20 tourists have 1 expert guide
Each site may only be visited once every 2/3 days
Captains of cruise ships are responsible for observing this
What is the IAATO?
International Association of Antarctic Tour Operators
What does IAATO do?
Lay out rules for cruise ships to adhere to when taking parties ashore
Is stress brought to penguins when tourists visit?
No
Is stress brought to tern colonies when tourists visit?
Yes
Do tourists cause litter?
No, there is more waste from research stations
What percentage of landing sites showed wear and tear due to tourism?
5%
What are 6 concerns about tourism in Antarctica?
The summer tourist season coincides with peak wildlife breeding season
The land-based installations and wildlife are clustered in the few ice-free locations on the continent
The demand for freshwater is difficult to meet
Visitor pressure is felt on cultural heritage sites
There is evidence that over-flying by light planes and helicopters causes some stress to breeding colonies of penguins and other birds
The unique legal status of Antarctica makes the enforcement of any code of behaviour difficult
What cultural heritage sites are there in Antarctica?
Old whaling and sealing stations as well as early exploration bases
