Polynya

A polynya is a persistent area of open water surrounded by sea ice, kept ice-free either by warm water rising from below (sensible-heat polynyas) or by winds and currents pushing newly formed ice away (latent-heat polynyas). Coastal latent-heat polynyas like the Ross Sea polynya are ice factories and sites of dense-water formation that feeds Antarctic Bottom Water. They are also biological hotspots, supplying early-season light and nutrients to plankton and the predators above them.