The Dead Sea, Earth’s lowest point, is known for its extreme salinity and unique floating experience. Scientists are now studying massive salt formations beneath its surface, driven by evaporation, temperature changes, and human impact.
The Dead Sea is a unique body of water located at the lowest point on Earth’s surface and has an extremely high salinity, about ten times greater than that of the ocean. Because of this, the water is very dense, allowing people to float easily. Floating in the Dead Sea is a popular activity enjoyed by tourists.
However, scientists have found something surprising occurring beneath the surface. The formation of massive salt deposits, often referred to as “salt giants,” can stretch for many kilometres and reach thicknesses of over a kilometre. According to Professor Eckart Meiburg, a mechanical engineer at UC Santa Barbara, the Dead Sea is the only place on Earth where scientists can observe these salt formations developing in real time. The research was published in Annual Review of Fluid Mechanics.
Other seas like the Mediterranean and Red Sea also have substantial salt layers buried deep underneath them. What makes the Dead Sea special is that the process of salt buildup is still taking place.
Why the Salt Builds Up
Now scientists are studying how these salt grains form and evolve over time. The Dead Sea is classified as “terminal lake,” meaning it has no natural outlet. Water leaves the lake only through evaporation, which is very high due to the hot and dry desert climate. As water evaporates, it leaves behind salt and various minerals, gradually forming layers over time.
Researchers say that human activities have worsened the situation in recent years. The Jordan River, which supplies water to the Dead Sea, has been dammed and diverted, leading to a significant drop in the lake’s water levels. This rapid decline in water levels accelerates the evaporation process, causing more salt to accumulate.
Temperature plays a crucial role in the formation of these salt structures. In the past, the Dead Sea had distinct layers of water. The warmer, less salty water sat on top, while the cooler, saltier water remained at the bottom. This stable layering helped keep the salt concentrated near the bottom.
However, this changed in the early 1980s. With less freshwater inflow and increased evaporation, the surface became just as salty as the deeper layers. This allowed the water layers to mix more easily, transforming the lake into “holomictic,” where mixing occurs at least once a year.
Now, the lake only maintains distinct layers during the warmer months, which last about eight months each year.
Why It Matters
In 2019, researchers found that halite crystals, or rock salt, were forming in the lake during the summer, a time when it usually wouldn’t happen. In summer, even though the surface water is warmer, evaporation increases which makes the top layer saltier. Surprisingly, some of the salt still dissolves due to the warm temperature. This unusual process is called “double diffusion.’ In this phenomenon, parts of the salty top layer cool and sink, while the bits of the cooler, less salty bottom layer warm up and rise. As this mixing occurs, salt crystals can form during the warmer months too.
These changes in temperature, evaporation, and water density, along with natural currents and waves, all contribute to the shaping of salt deposits into various forms.
Studying the Dead Sea not only provides insights into a fascinating natural wonder but also helps scientists understand how salt forms and moves in extreme environments. This research could help in understanding coastal erosion in arid areas, especially as sea levels change.