|halocline (hāl'ə-klīn') Pronunciation Key
A relatively sharp discontinuity in ocean salinity at a particular depth. In general, water with a higher concentration of salinity sinks below water that is less saline; therefore, saltier haloclines lie below less salty ones. An exception is the surface halocline of the Arctic Ocean, which is both colder and more saline than the warmer Atlantic water beneath it and which protects the polar ice from melting from below.
vertical zone in the oceanic water column in which salinity changes rapidly with depth, located below the well-mixed, uniformly saline surface water layer. Especially well developed haloclines occur in the Atlantic Ocean, in which salinities may decrease by several parts per thousand from the base of the surface layer to depths of about one kilometre (3,300 feet). In higher latitudinal areas of the North Pacific in which solar heating of the surface waters is low and rainfall is abundant, salinities increase markedly with depth through the halocline layer. Pycnoclines, or layers through which water density increases rapidly with depth, accompany such haloclines inasmuch as density varies directly with total salt content.
Learn more about halocline with a free trial on Britannica.com.