A 'pycnocline' is a layer across which there is a rapid change in water
density with
depth. In
freshwater environments such as
lakes this density change is primarily caused by water
temperature, while in
seawater environments such as
oceans the density change may be caused by changes in water temperature and/or
salinity.
See also
★
Halocline
★
Isopycnal
★
Thermocline