The polar seas Flashcards
(16 cards)
Why are polar landscapes so cold?
Due to Earth’s tilt and orbit, low solar angle, high albedo, and extensive atmosphere sunlight must travel through
Sunlight less intense and more reflective at high latitudes
What is albedo and how does it affect polar climate?
Albedo is the reflectance of solar radiation, which is high over ice, reflecting heat away
Helps maintain cold temperatures
What are two key differences between the Arctic and Antarctic Oceans?
The Arctic is smaller, shallower, and surrounded by land; the Antarctic is larger, deeper, and surrounds a landmass
Affects circulation, nutrient flow, and ecosystem structure
What role does river runoff play in the Arctic Ocean?
It adds nutrients and pollutants, especially from surrounding land
Unlike Antarctic, which has no river runoff
What current dominates the Antarctic Ocean and why is it important?
The Antarctic Circumpolar Current (ACC) drives nutrient-rich upwelling and mixes Antarctic and sub-Antarctic waters
Key to high productivity
Why is sea ice ecologically important in polar regions?
It supports unique communities (e.g., algae, krill), offers a surface habitat, and influences light and nutrient availability
Melting ice enhances productivity
What is the ecological role of krill in the Southern Ocean?
Krill are a central species in the food web—consumed by birds, fish, and mammals
Huge swarms can cover over 450 km²
What happens at the ice edge during spring and summer?
High seasonal productivity occurs due to increased light and nutrient release
Supports plankton blooms and higher trophic levels
What is ice scour and why is it ecologically significant?
Ice scour is when moving ice scrapes the seafloor, removing organisms and altering habitats
Influences benthic community structure
How does the Arctic seafloor differ from the Antarctic?
The Arctic has wide continental shelves with detritus and kelp; the Antarctic has steep shelves and more frequent scouring
Results in different benthic communities
What kind of benthic feeders dominate the Arctic?
Deposit and suspension feeders like polychaetes, clams, and soft corals
Also includes predatory fish and walruses
What traits are common in Antarctic benthic animals?
Slow metabolism, gigantism, and dominance of suspension and deposit feeders
Due to cold water and high o2 levels
What is a key fish adaptation to freezing polar waters?
Production of antifreeze glycoproteins by species like notothenioids
Prevents ice crystal formation in blood
Why is gigantism common in Antarctic marine species?
Due to slow growth rates and high dissolved oxygen in cold water
Leads to unusually large body sizes
Why is sea ice important for polar birds and mammals?
It serves as a platform for resting, raising young, and hunting
Which polar region has higher species endemism?
Antarctic
Many species are not found anywhere else on earth
