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Comparative aspects of the biology
of the Arctic and Antarctic marine
ecosystems
The Arctic is an
ocean surrounded by
land.
The Antarctic is a
continent
surrounded by
ocean.
High Arctic brackish
Boreal littoral
High Arctic Shallow
High Arctic Abyssal
Zones of the High Arctic
Marine Ecosystem
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
The importance of epontic (subice)
productivity to pagophilic species and to
those that feed near the ice edge
Ambio 1989
Key species
in the Arctic
marine food
web
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.
Distribution of arctic seabird colonies in relation to
recurring polynyas and shoreleads
M. Mallory
Characteristics of the Antarctic Marine Ecosystem:
- coldest, driest, windiest and least accessible area
- I/10th of earth’s 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, 90%annual 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
Maximum ice
Cover – October
Minimum ice
Cover – February
Euphausia
superba
The Antarctic krill
Key species in
the Antarctic
marine food
web
Weddell seal feeding on an
Antarctic tooth fish –
Dissostichus mawsoni
Emperor penguins
“flying” underwater
as they search
for food