arctic ocean arctic sea ice ecology arctic shrinkage atmosphere biosphere celsius climate continental shelf digital object identifier drift ice drift station fahrenheit fast ice frazil ice glacier grease ice gulf of bothnia ice class ice pier ice shelf iceberg icebreaker kara sea krill marine modeling and analysis branch nathaniel bowditch ocean pancake ice polar bear polar ice packs polar region polynya pycnocline ross sea seawater slush snow southern ocean supercooling sympagic ecology vize island vladimir wiese white sea zhubov scale