Comparative aspects of the biology of the Arctic and Antarctic marine ecosystems

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Comparative aspects of the biology of the Arctic
and Antarctic marine ecosystems
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The Arctic is an ocean surrounded by land.
The Antarctic is a continent surrounded by ocean.
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High Arctic brackish
Boreal littoral
High Arctic Shallow
Zones of the High Arctic Marine Ecosystem
High Arctic Abyssal
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Characteristics of the Arctic Marine
Ecosystem - 1-2 million years old - marine
fauna mainly derived from N. Atlantic - low
degree of endemism (no endemic genera) - absence
of intertidal fauna - reduction in productivity
away from continental shelf - ice-covered,
stratified layers, reduced mixing - long
circulation time - important factors influencing
life processes - light cyclical
availability - importance of euphotic zone -
nutrients phosphates, silicates, nitrates -
rivers refurbish nutrients coastally in summer -
critical importance of epontic (subice)
productivity - 15-30 of total productivity -
protracted phytoplankton bloom - influenced
by snow cover multiyear ice - terrestrial
predators, diversity of birds and mammals
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The importance of epontic (subice) productivity
to pagophilic species and to those that feed near
the ice edge
Ambio 1989
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Key species in the Arctic marine food web
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Typical coastal shore lead in the Beaufort Sea
Winds that alternate between onshore and
offshore maintain coastal shorelead polynya
systems along the coastlines of the mainland,
Hudson Bay, and high arctic archipelagos.
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Distribution of arctic seabird colonies in
relation to recurring polynyas and shoreleads
M. Mallory
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Characteristics of the Antarctic Marine
Ecosystem - coldest, driest, windiest and
least accessible area - I/10th of earths
surface, 98 ice-covered - -89o C, coldest
temperature on polar plateau - ice in middle of
continent 3 km thick - 20-40 million years old,
many different species - high degree of
endemism (70-90 in various groups) - absence of
intertidal fauna - most ocean north of 70o N -
ice cover much more variable, 90annual
change - 50 annual change in the Arctic -
prevailing winds from south stimulate ice
production and sinking of cold water along
coast, and coastal polynyas - no terrestrial
predators, replaced by marine predators - must
swim or fly to reach continent - low diversity
of birds and mammals - feed from the sea at
some level
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Minimum ice Cover February
Maximum ice Cover October
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Euphausia superba The Antarctic krill
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Key species in the Antarctic marine food web
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Weddell seal feeding on an Antarctic tooth fish
Dissostichus mawsoni
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Emperor penguins flying underwater as they
search for food
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