Halocline

In oceanography, a halocline (from Greek hals, halos 'salt' and klinein 'to slope') is a cline, a subtype of chemocline caused by a strong, vertical salinity gradient within a body of water.

[1] Because salinity (in concert with temperature) affects the density of seawater, it can play a role in its vertical stratification.

[3] In these regions, the halocline is important in allowing for the formation of sea ice, and limiting the escape of carbon dioxide to the atmosphere.

Haloclines are also found in fjords, and poorly mixed estuaries where fresh water is deposited at the ocean surface.

If fresh water is slowly poured over a quantity of salt water, using a spoon held horizontally at water-level to prevent mixing, a hazy interface layer, the halocline, will soon be visible due to the varying index of refraction across the boundary.

Arctic Ocean: Bathymetric map in the eastern Arctic basin showing water layers with corresponding depths. (NOAA Office of Ocean Exploration and Research) [ 2 ]
Halocline visible at the cenote Chac Mool, Mexico . The freshwater lies above the denser saltwater. In this photo, the visible water distortion from the halocline can be seen below the diver.
Plot of temperature and salinity in the Arctic Ocean at 85,18 north and 117,28 east dated Jan. 1st 2010. [ 6 ]