Definition: An aquatic biome that comprises systems of open-ocean and unprotected coastal habitats, characterized by exposure to wave action, tidal fluctuation, and ocean currents as well as systems that largely resemble these. Water in the marine biome is generally within the salinity range of seawater: 30 to 38 ppt.
Definition: Any enclosed water area in pack ice other than a lead, not large enough to be called open water. When frozen over, a polyna becomes an ice skylight from the point of view of the submariner.