Hydrogen Sulfide layers in water

[Tamara Thomsen]

From my experience, the hydrogen sulfide layers settle in between layers of water with differing densities.  In the Bahamas we were finding it at layers with different salinities(sea water on bottom and brackish on top).  If I remember correctly from quarries that I have experienced this in, it may be associated with a thermocline and the water density diferences due to the termperature differential (however so slight) may be what is trapping the gas in the water column.  For those of you that have expereinced this effect more recently, you'll have to confirm or deny this for me.  This may answer both questions (JohnF and Maka) that are up and unanswered. 

What we have to our advantage here in the north, is that a majority of us that punch through these layers are wearing drysuits, possibly dry gloves, hoods, etc.  We have little skin exposed directly to the water at best!