The L'Atalanta lake and its neighbors the Urania and Discovery lakes are about 35,000 years old . They were formed by salt deposits dissolving out of the Mediterranean Ridge and collecting in deep depressions at the bottom of the Med . 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 3000 m deep .