Bahamas Out Island News

On the long list of reasons why few scientists have dared plumb the mysteries of the Bahamas' famed blue holes, the toxic swamp gas actually rates pretty low. Hydrogen sulfide gas, a byproduct of bacteria and plant debris rotting for eons, gets trapped in a murky zone called the halocline where dense salt water mixes with fresh rain water floating above. In some submarine caverns, swimming through the foul layer leaves divers with burning skin, retching stomachs or worse. That says a lot about the daunting challenges below: utter blackness, uncharted and claustrophobic passages, walls that crumble into clouds of silt, shifting currents and extreme depths that demand exotic diving gear, elaborate safety systems and Zen cool. For Kenny Broad, a University of Miami scientist who led a National Geographic Society-backed expedition that made 150 dives into blue holes on Abaco, Andros and other islands, the rewards far exceeded the risks.

http://www.tribune242.com/09242010_Deep-water-sharks_news_pg14