Low temperatures, low salinity, high plankton levels and correspondingly green color generally characterize Polar marine waters. Extensive ice is also typical of the polar ocean, both in terms of cover by sheets and in the form of drift ice and icebergs carried by polar currents.
Ice provides important habitat in the form of breeding platforms from which seals breed and search for food. Polar bears in the Arctic, and penguins in the Antarctic, also rely on the ice for habitat. Species diversity is enhanced in the Polar seas by a system of warm water upwellings that create breaks in the ice. The corresponding open areas support numerous invertebrates, fish, sea birds, and marine mammals - the result of a broad based food chain.
The Weddell Sea and Peninsular Antarctica were identified as the most productive and diverse ecoregions of the Antarctic large marine ecosystem, while the Bering, Beaufort, &Chukchi Seas and Barents Sea ecoregions are arguably 2 two most diverse and productive Arctic marine ecosystems.