Saltwater Lakes: The World’s Briny Basins

What are saltwater lakes?

Saltwater lakes are bodies of water that carry significantly higher salt content than typical seawater. They range from moderately saline to hypersaline, where the water becomes extremely briny. Many salt lakes are endorheic basins, meaning they have no outlet to the sea. Water flows in from rivers or groundwater but leaves mainly by evaporation, so minerals and salts stay behind and become concentrated over time.

Basic definition and salinity range

Saltwater lakes include environments that are too salty for most freshwater organisms but too varied to fit a single label. Seawater is about 3.5% salt by weight, and salt lakes can be far saltier. Some lakes reach extreme salinities, forming briny ecosystems unlike those in ordinary rivers or lakes.

Endorheic basins and mineral accumulation

In many arid and semi-arid regions, rivers drain into closed basins with no external outlet. Evaporation removes water but leaves dissolved minerals behind, gradually increasing salinity. The result is vivid, sometimes shimmering, landscapes where minerals like halite (rock salt) can precipitate and form crusts along the shore.

How they form and why they’re salty

Salt concentrations in lakes rise and fall with climate and hydrology. The core process is simple: water enters the basin, leaves mainly by evaporation, and salts stay behind.

Evaporation and concentration

Hot, dry conditions drive rapid evaporation. As fresh water leaves, the remaining water becomes saltier. In some cases, the lake can become so saline that only specialized organisms can survive, while the water itself remains liquid enough to support microbial life.

River inflows and mineral sources

Rivers can bring dissolved minerals from the landscape, including salts and gypsum. Groundwater can also leach minerals from surrounding rocks. When evaporation concentrates these minerals, they contribute to the lake’s distinctive chemistry and, in some places, to visible crystals or colorful microbial mats.

Where they’re found around the world

Saltwater lakes are found in many regions, but they are especially common in dry, closed basins where evaporation is high.

Global hotspots

Desert basins in North Africa, the Middle East, Central Asia, and parts of North America host notable salt lakes. These lakes often appear as vast, pale or pinkish expanses in satellite images, changing with rainfall and seasonal evaporation.

Notable examples

Famous saltwater lakes include the Dead Sea, which is known for its extremely high salinity and buoyant waters, and the Great Salt Lake in North America, a large, variable-brine lake in Utah. Other well-known examples join a broader family of saline lakes that scientists study for clues about climate, geology, and extremophile life.

Life in salty waters

Despite extreme salinity, saltwater lakes can host thriving ecosystems, especially microorganisms and small invertebrates adapted to brine conditions.

Microbial life and halophiles

Halophiles are microorganisms that tolerate or require high salt levels. They can form colorful microbial mats and contribute to unique biogeochemical processes in these lakes. In some lakes, photosynthetic algae or bacteria provide primary production that supports larger life forms.

Ecosystem services and research value

Saline lakes serve as natural laboratories for studying adaptation, the limits of life, and how climate and hydrology shape ecosystems. They also offer educational value and, in some places, opportunities for salt harvesting or tourism that emphasizes natural beauty rather than extraction.

Why they matter and how they’re changing

Saltwater lakes reflect broader environmental patterns and pressures that affect landscapes worldwide.

Climate connections

Changes in precipitation, drought frequency, and warming temperatures alter evaporation rates and inflow. In many regions, reduced river input and higher evaporation raise salinity further, stressing resident organisms and altering lake chemistry.

Conservation and safe enjoyment

Salt lakes are valuable for ecology, geology, and culture, yet they can be sensitive to pollution, water management practices, and mining. Preserving their natural state supports biodiversity and scientific insight while still allowing people to appreciate their striking beauty and distinctive landscapes.