Dead Sea 342 parts per thousand (in 2002), and a temperature that swung between and . Underneath a zone of transition, the lowest level of the Dead Sea had waters of a consistent temperature and complete saturation of sodium chloride (NaCl). Since the water near the bottom is saturated, the salt precipitates out of solution onto the sea floor. Beginning in the 1960s, water inflow to the Dead Sea from the Jordan River was reduced as a result of large-scale irrigation and generally low rainfall. By 1975, the upper water layer was saltier than the lower layer. Nevertheless, the upper layer remained
Dead Sea lake capable of supporting marine life. A similar prophecy is stated in , which says that "living waters will go out from Jerusalem, half of them to the eastern sea [likely the Dead Sea] and half to the western sea [the Mediterranean]." Aristotle wrote about the remarkable waters. The Nabateans and others discovered the value of the globs of natural asphalt that constantly floated to the surface where they could be harvested with nets. The Egyptians were steady customers, as they used asphalt in the embalming process that created mummies. The Ancient Romans knew the Dead Sea as ""Palus Asphaltites""