Original: L'Atalante and its neighbors the Urania and Discovery deep hypersaline anoxic basins ( DHABs ) are at most 35,000 years old , and were formed by Messinian evaporite salt deposits dissolving out of the Mediterranean Ridge and collecting in abyssal depressions about deep .
Simplified: This halocline between the seawater above and the brine below has many bacterial and archaeal cells : they are chemoautotrophs , which feed on ammonia from the brine but can not function without some oxygen .