Why is the Dead Sea saltier than ocean water?

The Dead Sea is located in a low-lying desert, where the rate of evaporation is faster than that of the ocean, making the lake water saltier than seawater due to its higher salt concentration.

Salt accumulates in mountains around the shores of the Dead Sea. Photo: Shutterstock

The Dead Sea is an inland lake bordering Jordan, Israel, and Palestine, according to Live Science. It is recognized as one of the world's most saline lakes.

No fish, birds, or plants can survive in the highly saline environment of the Dead Sea. The water there is nearly 10 times saltier than normal seawater.

Salt on Earth

According to the U.S. National Oceanic and Atmospheric Administration (NOAA), the Earth's oceans contain approximately 3.5% salt. This salt originates from rocks on land. Acid in rainwater breaks down the rocks, trapping ions within them and carrying them to the sea. Most of these ions are sodium and chlorine, two ions that combine to form salt in the ocean.

If we removed the salt from water, we would obtain approximately 50 quadrillion tons of salt, forming a salt layer 153 meters thick covering the Earth, equivalent to the height of a 40-story building.

Salt in the Dead Sea

NOAA estimates that the Dead Sea water is 5-9 times saltier than seawater. Seawater salinity varies with depth. At a depth of 100 meters below sea level, the water is saturated with salt and cannot dissolve any more, causing salt to accumulate at the bottom of the sea.

The Dead Sea lies in a valley stretching over 1,000 km, beginning in the Sinai Peninsula and extending northward into Türkiye. This area is the lowest point on Earth, 429 meters below sea level. A series of lakes once existed in this valley and disappeared 15,000 years ago, leaving only the Dead Sea, according to the Minerva Dead Sea Research Centre (MDSRC).

Freshwater from the Jordan River is the only source of water flowing into the Dead Sea. However, there are no canals or streams carrying water from the lake to the ocean. Water accumulates in the Dead Sea and evaporates faster than seawater in the ocean, resulting in a higher salt concentration than the ocean, MDSRC explains.

The Dead Sea is dying.

In recent years, human activities such as extracting water from the Jordan River for agricultural irrigation have depleted the valuable water source that replenishes the Dead Sea, causing the lake's water to become increasingly saline.

In fact, the Dead Sea is gradually disappearing. Each year, the lake's water level drops by about one meter, according to a 2010 study published in the journal Environmental Economics. Researchers say the Dead Sea's water level has dropped by about 30 meters since the beginning of the 20th century.

Another study suggests that, even without human intervention, the Dead Sea is at risk of disappearing. In 2010 and 2011, scientists drilled to explore the lakebed's geology. They discovered that, approximately 120,000 years ago, the Dead Sea had completely dried up, leaving only the salt layer on the surface.

The future of the Dead Sea remains uncertain. Although there are many signs that this lake may disappear, in 2011 it continued to surprise the scientific community.

An unmanned submersible has for the first time explored previously uncharted depths and discovered a freshwater spring containing bacteria at the bottom of the Dead Sea. Scientists are looking forward to uncovering even more mysteries about this lake.

According to VNE