under ice

“It's one of the planktons we glaciologists commonly see in the oceans under ice shelves.”

Deception Point

“Lieutenant Hansen knows that a diesel engine is never, never lit up when a submarine is submerged -- unless with a snorkel, which is useless under ice -- for a diesel not only uses air straight from the engineroom atmosphere, it gulps it down in great draughts and would soon remove all the air in the ship.”

Ice Station Zebra