Since 2014, the inflow of groundwater below the surface of the Dead Sea has been investigated in collaboration with the Helmholtz Centre for Environmental Research (UFZ). Prof Broder Merkel and Dr Thomas Pohl were on diving missions in Engedi, Israel, in November 2012, November 2014 and April 2018.
There is a more detailed report on the last mission below:
Diving at the Dead Sea
From 14 - 26 April 2018, Prof. Broder Merkel and Dr Thomas Pohl from the Scientific Diving Center were on a ten-day research mission at the Dead Sea. Here they investigated submarine groundwater sources in the extremely salty water (density 1.24 g/cm2), which are associated with the sharp drop in the water level.
The water level of the Dead Sea sinks by around one metre every year, causing cavities to form in the coastal area, which sometimes collapse and lead to serious damage to buildings and roads and endanger human lives. The Dead Sea has only one major tributary, the Jordan River, from which water is drawn for the regional population (drinking water and irrigation). The water level in 2018 is minus 432 metres below sea level.
The Freiberg researchers, who were invited by the Geological Survey of Israel, are working together with scientists from the Helmholtz Centre for Environmental Research Halle-Leipzig and Ben-Gurion University in Jerusalem. They are continuing a series of underwater explorations from 2012 and 2014.
In order to recognise at an early stage where the dangerous sinkholes are occurring, the salt leaching in the subsurface must be investigated. To do this, the scientists take samples from submarine groundwater sources at depths of three to 20 metres under water. These are now being analysed in German and Israeli laboratories.
The excursion was characterised by dry conditions, air temperatures of up to 45°C and water temperatures of up to 27°C. As the sites are not always accessible by off-road vehicle, the scientists have to carry their equipment, which weighs around 400 kilograms in total, through the inaccessible terrain to the water themselves.
Due to the high salt content of the Dead Sea, the divers need around 60 kilograms of additional weight on their bodies to be able to work underwater at all. A full face mask protects the eyes and mouth from the extremely aggressive salt brine. Sufficient fresh water must be available after each dive to rinse the brine off the divers and their equipment.
