Salt chimneys are precipitated in the Dead Sea at the interface between saline groundwater and the Dead Sea water.. Microbial community in salt chimneys in the Dead Sea

Subaquatic discharge of fresh and brackish groundwaters into lakes and oceans is a common process. At locations such as the Mid Ocean Ridges and abyssal submarine volcanoes groundwater discharge may be associated with formation of chimney structures, mainly composed of sulphides and carbonates ({Spiess:1980wy}; {Tiercelin:1989bs}, {Davis:2008vo}). These structures grow by rapid precipitation at the orifice due to changes of temperature, pressure, pH-value and redox-potential.Chimneys built of very soluble salts have not been described yet. Here we present halite chimneys as a new form of coldwater smokers in hypersaline lakes. We found such structures rising up from the bottom of the Dead Sea. They result from the submarine discharge of saturated halite dissolution brines into salt lake, which is at halite saturation and holds remarkable chloride excess. At the interface wit the lake brine, halite precipitates instantaneously, forming chimneys that grow upward due to the lower density of the emerging fluids.Salt chimneys are related to the leaching of massive halite deposits, a process that occurs in the marginal sediments of the Dead Sea and coincides with both the decreasing water level of the lake and the excessively increasing occurrence of on- and offshore sinkholes ({Abelson:2017da}). Thus, these chimneys are indicators of subsurface cavitation and may provide a potent, predictive tool to locate areas that may collapse in the future.