A) Very-large-bodied invertebrates in bottom communities
B) Very high phytoplankton productivity
C) Ice as a source of algal production and deposition on the sea floor
D) Dominance of penguins

A) Killer whales now can hunt them more effectively
B) Leopard seals can leap out of the water and raid nests
C) Krill, the food of penguins, grows better under the floating ice
D) All of the above

A) Arctic primary productivity is very low and benthic abundance is comparable to the deep-sea soft bottoms
B) Arctic food webs are characterized by few large carnivores
C) Unlike the Antarctic, ice algae has no role in flow through food webs
D) Arctic primary productivity is much higher than that which is typical of the Antarctic