Pycnocline

A pycnocline is the <a href="/facts/Cline_(hydrology)/h0rv7qov">cline</a> or layer where the <a href="/facts/Density/92p6hh9I">density</a> <a href="/facts/Gradient/TsR7uukj">gradient</a> (⁠∂ρ/∂z⁠) is greatest within a body of water. An <a href="/facts/Ocean_current/vfwdGwPY">ocean current</a> is generated by the forces such as breaking waves, temperature and <a href="/facts/Salinity/X6mB1YAM">salinity</a> differences, wind, <a href="/facts/Coriolis_effect/SqCyUY6d">Coriolis effect</a>, and tides caused by the gravitational pull of celestial bodies. In addition, the physical properties in a pycnocline driven by density gradients also affect the flows and vertical profiles in the <a href="/facts/Ocean/8W8lYgjD">ocean</a>. These changes can be connected to the transport of heat, salt, and nutrients through the ocean, and the pycnocline diffusion controls upwelling.
Below the mixed layer, a <a href="/facts/Stable_stratification/HFSsD0cm">stable density gradient</a> (or pycnocline) separates the upper and lower water, hindering vertical transport. This separation has important biological effects on the ocean and the marine living organisms. However, vertical mixing across a pycnocline is a regular phenomenon in oceans, and occurs through shear-produced <a href="/facts/Turbulence/NpgFUhG5">turbulence</a>. Such mixing plays a key role in the transport of nutrients.

Pycnocline open-in-new

Pycnocline