When was the first discovery of a halocline made?

Question

I saw the recent "Planet Earth" series on The Discovery Channel. A couple divers in a subterranean cave in Mexico swam up from the saltier water up to the fresh water and it was startling how distinctly clear that boundary (halocline) was as a dividing barrier. Since these divers and that halocline was filmed in a subterranean cave full of water and quite impossible to get to without modern technology (or without coming alive to tell about it), I would like to know when this discovery first took place and by whom.

Answer 1

The existence of such a line is implicit in the fact that fresh water floats on salt water. In fact, if a plastic bottle is filled with salt water and just a little air is added, until it just barely sinks in fresh water, it will sink until it floats on the layer. (Or mix 50% saltwater and 50% fresh depending on whether the bottle will float on saltwater when full of the mixture.)
Submarines had to deal with the situation in WWI & II because when coming down a river, they could not sink into the salt water except by blowing air (becoming heavier.)
I would expect that divers in the Mediterranian who were going for sponges, crabs, oysters, etc., on the bottom near flows of fresh water (rivers or heavy rain) were aware of it, perhaps since Greek times.

Answer 2

Haloclines were mentioned in the Quran more than 1450 years ago.....Allah knows best of what he created and teaches us if we are willing to learn.

Answer 3

read the quran in 25:53 :)