Researchers have found that there are chimneys reaching up to a meter tall on the floor of the Dead Sea. These structures result from the natural crystallization of minerals from groundwater that has a very high salt concentration seeping up from the lake bed, according to a report published in the journal Science of the Total Environment. This discovery marks the first time these vents have been identified and they serve as an important early warning sign for sinkholes. These sinkholes, which can create large craters, are common in the vicinity of the Dead Sea and represent a considerable risk to the surrounding population.
Researchers have found that there are chimneys reaching up to a meter tall on the floor of the Dead Sea. These structures result from the natural crystallization of minerals from groundwater that has a very high salt concentration seeping up from the lake bed, according to a report published in the journal Science of the Total Environment. This discovery marks the first time these vents have been identified and they serve as an important early warning sign for sinkholes. These sinkholes, which can create large craters, are common in the vicinity of the Dead Sea and represent a considerable risk to the surrounding population.
The Dead Sea is a very active environment. Its water level has been decreasing by about one meter each year for over 50 years, primarily because it is disconnected from major tributaries and is losing significant amounts of water through evaporation due to severe heat and drought. The water surface has now reached approximately 438 meters below sea level. This reduction in the lake’s size, which borders Israel, Jordan, and the Palestinian-administered West Bank, greatly affects the surrounding groundwater. The lowering of the groundwater level makes it increasingly challenging for neighboring countries to access these essential water resources. Dr. Christian Siebert, a hydrogeologist at UFZ, has been researching the changing dynamics of the groundwater system in this area, focusing on how aquifers are rerouting through the rock layers on land and beneath the Dead Sea. A team of divers he sent out discovered chimney-like vents at the bottom of the lake that release a glowing fluid.
“These structures are remarkably similar to black smokers found in the deep ocean, but the processes involved are entirely different,” explains Siebert. A collaboration of scientists from various fields—including mineralogy, geochemistry, geology, hydrology, remote sensing, microbiology, and isotope chemistry—across ten research institutions participated in the investigation and analysis of this phenomenon.
Unlike black smokers, which release heated water rich in sulfides at depths of several thousand meters, the researchers found that the highly salty groundwater is flowing out through these chimneys at the Dead Sea’s bottom. So, where does this salt originate? The answer lies in the groundwater from surrounding aquifers that infiltrates the salty sediments of the lake, dissolving ancient layers of rock that mainly consist of halite. This resultant brine then flows into the lake.
“Due to the slightly lower density of this brine compared to the water in the Dead Sea, it rises like a jet, creating a smoky appearance, even though it’s actually a saline fluid,” explains Christian Siebert.
When this fluid interacts with the lake water, the dissolved salts, particularly halite, spontaneously crystallize upon exiting the lake bed, forming the vents that have now been observed for the first time globally. These structures can grow several centimeters each day. Many of the tall chimneys measure between one to two meters, but some are giant formations reaching over seven meters and measuring more than two to three meters in diameter. Tiny amounts of 36Cl, a space-derived radioisotope, along with genetic evidence of freshwater microbes found in the chimney waters, confirm that these structures originated from the surrounding aquifers. The salts were absorbed only in the final moments before entering the Dead Sea.
These white smokers play a crucial role as early indicators for sinkholes. Sinkholes can range up to 100 meters wide and 20 meters deep, with thousands having appeared around the Dead Sea in recent decades. They result from the karstification of the underlying soils, leading to the dissolution of thick salt layers and the formation of large cavities that can cause ground collapses.
“Currently, it’s impossible to predict where the next sinkholes will form. They are dangerous and threaten both agriculture and infrastructure,” notes Christian Siebert. The research team found that these chimneys have emerged in areas where the ground surface collapsed over a large area, indicating that the karstification process is particularly active there.
“This makes the white smokers an excellent tool for predicting regions that may be at risk of collapse soon,” Siebert elaborates. Autonomous watercraft equipped with multibeam echosounders or side-scanning sonar systems could be utilized to create precise maps of these chimneys. “This method would be the first of its kind and would effectively help in identifying areas vulnerable to imminent collapse.”
