>As a result, whilst it’s possible to form dense waters at the surface of the ocean (which can sink), there is no process that can reduce the density of the resulting deep waters, and thereby bring them back to the surface.

Is this why those mini-brine lakes form on the seafloor in some areas? Like will the densest, most saline waters end up all coalescing together deep in the ocean until the salt content is so concentrated that it approaches saturation? Or are those brine pools the result of something geological instead? (I know that that they’re associated with methane cold seeps)