How Salty is the Dead Sea?

Bordered by Israel and Jordan, the Dead Sea has a reputation as the saltiest sea in the world, with a salinity of around 34%, about 10 times as salty as the Atlantic and Pacific Oceans. And while there are a handful of lakes and lagoons that have higher salinities, the Dead Sea is the deepest hypersaline lake – and certainly the most widely known. But what is it that makes the Dead Sea so salty? And how does that hypersalinity affect the ecosystem that surrounds it?

Why is the Dead Sea so salty?

The Dead Sea salt content is derived from rocks on the land that are eroded by rainwater. All rainwater contains some acids that form when carbon dioxide combines with water, creating a mild carbonic acid solution. These acids slowly break the rocks down over time, creating charged particles called ions that eventually find their way to the Dead Sea, oceans, and other bodies of salt water through runoff. Of all the ions created by rainwater, sodium and chloride are the most common, comprising about 90 percent of the oceans’ ion content; when they enter the ocean, their charges attract each other. And what happens when sodium (Na) and chloride (Cl) combine? We get one of the most common chemical compounds around, NaCl – good, old salt!

How much salt is in the Dead Sea?

According to the National Oceanic and Atmospheric Association (NOAA), a single cubic mile of ocean water contains about 120 million pounds of salt. Put it another way, if all the salt were removed from the oceans of the world and spread over the land areas, it would create a layer about 500 feet (150 meters) tall, That’s about the same height as a 40-story building.

And that’s just the oceans. The Dead Sea salt concentration is, of course, much higher. The deeper you dive into the Dead Sea, the higher the salinity level becomes. At about 300 feet (100 meters) below the surface, salt becomes so concentrated, it begins to precipitate or form crystals that fall to the sea floor. That’s where the salt comes from; but why does it collect in the Dead Sea?

How was the Dead Sea formed?

The Dead Sea is located in the Jordan Rift Valley, a long valley created by a geologic fault line (called a rift). In addition to being one of the saltiest bodies of water on the face of the Earth, the Dead Sea is also located at the lowest elevation on the planet – more than 1,400 feet (about 430 meters) below sea level. At one point, a chain of lakes dotted the 620-mile-long valley, but by about 15,000 years ago, all had disappeared except for the Dead Sea (which itself is a vestige of the larger Lake Lisan that extended from the Sea of Galilee in the north to about 20 miles (35 km) south of the southern tip of the present Dead Sea, according to the Minerva Dead Sea Research Center).

The Dead Sea has one tributary – the Jordan River. Once the water from the river enters the lake, there’s nowhere else for it to go – no way for it to flow out. Exposed to the intense heat of the desert sun, the water in the sea evaporates more quickly than in the ocean, where tides and currents keep water flowing from one area to another, intensifying the salinity levels. Plus, dams and other human activities have diverted some of the river’s water from the Dead Sea, which leaves less water to dilute the salt content. This also means that the Dead Sea is slowly drying out, so if you haven’t been to this amazing place, this is the right time to book your next vacation!

Can anything live in the Dead Sea?

With such a high salt content, it’s not surprising that the shores show no evidence of plant life, and the sea itself contains no fish or other “normal” sea life. In fact, the shores of the Dead Sea offer an almost lunar-like landscape, covered with salt residues and formations that glitter in the sun.

But despite its barren appearance, the Dead Sea does offer some surprises. In 2011, scientists delved deeper than ever before into the Dead Sea and discovered a series of freshwater springs surrounded by thriving colonies of tiny microbes. Probably, one of the most famous organisms that can happily survive in such a severe environment is the Dunaliella algae, which is widely known for its health benefits. Although it’s not a medicine, Dunaliella algae contain rich concentrations of beta-carotene, essential vitamins, and antioxidants. There’s also a lot of “life” on the surface of the Dead Sea, which on most days is dotted by bobbing bathers buoyantly supported by the sea’s high salt content.

Such “super buoyancy” is just one of the hidden benefits of Dead Sea salt; the salts found in the Dead Sea are also rich in essential minerals that are important to good health. Just a little salt provides ample amounts of magnesium, potassium, calcium chloride, and bromides. What’s more, the high concentrations of these minerals – about 10 times that of ocean water – displace some of the sodium found in ocean water, leaving just a fraction of the sodium content found in salts from the Atlantic, Pacific, and Indian Oceans.

In fact, the health benefits of Dead Sea salt have been extolled for thousands of years, beginning with the ancient Egyptians and Romans. Early historical records show Roman historian Flavius Joseph wrote extensively about the salts’ health benefits, and the sea itself served as an early health spa for the Roman elite, including King Herod the Great.

So what’s in store for the Dead Sea? Historical evidence suggests the waters of the sea have risen and fallen over thousands of years. In fact, some research suggests the entire sea dried up about 120,000 years ago, leaving a vast and deep bed of salt in its wake. Today’s human activities near the sea and the Jordan River have strained the lake and its reserves. But the area remains a rich source of scientific and geologic study and research, and environmental groups from throughout the region and around the world remain dedicated to protecting the Dead Sea and ensuring it remains one of the world’s natural wonders.