sulfate reducing bacteria : hydrogen sulfide smells of rotten egg

A gut feeling
8 August 1998

Gail Vines
New Scientist Environment

WHAT'S the difference between the contents of your bowels and the noxious black sludge at the bottom of an estuary? Not a lot perhaps—particularly if you live on a diet of junk food. The same sulphur loving bacteria that give mud in estuaries and ocean sediments their pungent, rotten-egg smell may have invaded your gut. In the sea, they are notorious troublemakers with a penchant for corroding oil pipelines, and their effect on human passageways may be equally devastating...

These mud-loving organisms, officially known as sulphate-reducing bacteria, find plenty to feast on in the oxygen-free (anaerobic) sea sediments. That's because they can exploit both the hydrogen that comes from the fermentation of countless microbes in the stagnant mud, and the plentiful sulphate in seawater. The bugs make their own energy from these raw ingredients, converting sulphate to sulphite and then creating a poisonous waste product: hydrogen sulphide, with its telltale smell of rotten eggs. To humans, the compound is as toxic as cyanide. In water, it rapidly becomes highly corrosive sulphuric acid...

Full article:
http://environment.newscientist.com/article/mg15921465.400-a-gut-feeling.html