Sea-ice Opening

The Arctic Ocean is one of the coldest seas on Earth, with thick ice on the surface. In winter it stays dark for months, but in summer the sun shines all day and algae bloom under the ice. Openings in the ice, called leads and polynyas, let light and air into the water. Northern lights and rapid warming make this icy ocean both magical and fragile.

The Southern Ocean circles Antarctica with fierce winds, giant waves, and winter sea ice that doubles the continent’s size. It is full of life, with tiny shrimp-like krill feeding penguins, whales, seals, and seabirds. Its waters are linked by the strong Antarctic Circumpolar Current, a huge river of water moving around the globe. This ocean also stores carbon and helps regulate Earth’s climate.