_:b1218188 "The marine pycnocline describes a sharp change in the density of seawater (in relation to the gradients of the water mass surrounding it) in the marine water column. Pycnoclines are usually associated with thermo- and haloclines."^^ . _:b1218188 "PLB:plb"^^ . _:b1218188 . _:b1218188 "Wikipedia:Mixed_layer"^^ . _:b1218188 . _:b1218188 .