the Black Sea?

Question

I was reading a book one time about this sea, and it made some... interesting annalysis's of it. And curious if anyone knows if this is correct.
It said that this is actually a very very dangerous sea. If you go very deep (even in a ship) there is some sort of gas or something that cna be dangerous no matter what your in. No scuba diving is safe there. Also that it is a very huge on gas (i think methane but not sure). It said that some very weird creatures lived in its depths but they are only indiginous to this area because of the conditions there.

Answer 1

When our ship went through the Black Sea, I didn't notice any particular gas, but the entire thing smelled bad and was extremely full of jellyfish(called Medusa's by the locals). Even running the water through our evaporator water purifier, it still had a funny taste to it. On a cloudy day, looking at the shadow of the ship, the water was in fact black, and filled with sediment.

Answer 2

Sea gasses I have heard about are methane and carbon dioxide. Generally, you will find deposits of these gasses under the ocean floor, sometimes in large amounts and under high pressure. If one of these deposits erupts explosively, the resulting aeration of the water (gas bubbles) can cause it to become less dense (momentarily), and thus not be able to support the weight of a ship (or scuba diver), and then you will sink to the bottom and drown. I heard about deposits like this in what is known as the Bermuda Triangle.