That would work only if the fresh water is enclosed in some kind of container, like a plastic bag, otherwise it will mix with the salt water before reaching the surface.
Perhaps the difference in weight between 2 columns of water of equal height, but where one of the columns is of fresh water and the other of salt water, which causes a difference in pressure at their bases, can be exploited somehow for pumping the fresh water, i.e. for pushing it inside a pipe towards the surface, but with some kind of piston that separates it from the salt water.
It shouldn't be too difficult to fill up a balloon like container at the bottom of the sea with fresh water. Once the container is filled it will float up to the surface.
The container doesn't need to be super engineered, since it is filled with water so there is no pressure difference between the inside and outside.
adrian_b|6 months ago
Perhaps the difference in weight between 2 columns of water of equal height, but where one of the columns is of fresh water and the other of salt water, which causes a difference in pressure at their bases, can be exploited somehow for pumping the fresh water, i.e. for pushing it inside a pipe towards the surface, but with some kind of piston that separates it from the salt water.
sikonomial|6 months ago
The container doesn't need to be super engineered, since it is filled with water so there is no pressure difference between the inside and outside.