In March 2006 I went to Playa del Carmen and dived some of the cenotes with Yucatek, one of them is called Angelita. It is a more or less round sink hole in the jungle, which to the bottom is 200ft deep. After jumping into the water the viz was not as crystal clear as in the other cenotes, so we started our descent without seeing the bottom. After about 30ft the viz suddenly clears up dramatically and what was below seemed not from this world. In about 100ft is a thick, milky, off-white cloud layer. It seemed to me as if I was descending towards the clould layers of the planet Jupiter.
Above the cloud is fresh water, below it is the heavier salt water. The clould itself is hydrogen sulfate, which is formed by decaying vegetation that falls into the cenote from above.
We all gathered hovering just above the cloud layer, when Stephan, our guide, descended into it, his hand streched over his head. Slowely descending, the cloud consumed him like quick sand until only a hand was still visible and a blink later that was gone too.
Then it was my turn to descend through the cloud. Because of the heavier salt water below to make it through the clould and not get stuck in it, I needed to dump a little more air out of my BCD than was needed in just the fresh water. Going through the cloud I could taste the sulfur though the regulator and could not see the hand in front of my eyes. But after only a few feet I was below it, in a darker, brownish light. We were now kneeling on the bottom, which comes up from 200ft and goes though the cloud. There are branches laying around that fell into the cenote from the jungle trees above.
After a couple of minutes we ascend through the layer. The ground that comes up though the layer with it`s branches looks like an bizare tropic island sticking out of the clouds. Stephan stands on one of the branches on the island and jumps forward to fly superman style and disappears in the clouds below. After a short while we work our way up towards the surface, one can see the trees above the water.
So far, I have to say, was this my coolest and definitively most unusual dive I`ve ever done. None of the other cenotes are anything like Angelita.