For years, scientists viewed saline lakes as relatively simple ecosystems. They were thought to support only a limited range of aquatic life and simple food chains. But a new study published in Nature Communications suggests there is far more going on beneath the surface.
Researchers found that 200 species on the IUCN Red List rely on saline lakes in some way. More than half of these, 53%, are birds. Scientists believe the real number is even higher. Researchers have closely studied only a small fraction of the world’s saline lakes so far.
These lakes act like giant refuelling stops for birds crossing deserts and dry regions. Algae, brine shrimp, and other small creatures thrive in the salty water. This food does not exist in the dry land around the lakes. Flamingos, gulls, and wading birds land here to eat before long flights of thousands of kilometres.
The study’s authors make an important point. If people only judge saline lakes by what swims in them, they miss something bigger. Many species that never enter the water still depend on it to survive.
Another surprising finding is how different these lakes are from each other. Two lakes with the same salt levels can support entirely different life. Lake Krasnovishnevoye in Europe, Lake Urmia in Asia, and Seagull Lake in North America all share very high salt levels, over 100 grams per litre. That is three times saltier than seawater. Yet each lake has at least two endangered species that exist nowhere else on the list.
Lake Mahega sits in a volcanic crater in western Uganda. Its salt level tops 200 grams per litre. Scientists believe it is the only place on Earth where a certain rare mineral forms naturally today. This mineral is normally only found in ancient rock layers.
The researchers have studied 85 lakes so far. Each new lake studied revealed new species. There was no sign that this pattern would slow down. This suggests that many more unique species are still waiting to be found in unstudied lakes.
Tiny microbes living in these salty waters also carry genes unlike anything found elsewhere. These genes help proteins work in extremely salty conditions. Scientists think these discoveries could lead to new tools for medicine, industry, and biotechnology.
Some saline lakes are salty enough for fish. Lakes with lower salt levels, between 1 and 20 grams per litre, can support fishing industries. In lakes where fishing happens, catches average 2.2 tonnes per square kilometre each year. That is close to the top catch rates seen in freshwater lakes, which reach about 2.5 tonnes.
The study looked at 11 types of benefits these lakes provide to people and nature. But researchers say there are many more hidden benefits as well. These include helping to prevent climate disasters linked to drying land and protecting nearby farms from damage.
Because saline lakes offer so much, the study argues they deserve strong protection. Most of these lakes have no rivers flowing out to the ocean. Their water levels depend on a careful balance between water flowing in and water evaporating out. Climate change and the extraction of water for human use make these lakes extremely sensitive.
Professor Dave Ryves from Loughborough University helped lead the research. He worked alongside Dr Keely Mills and more than 60 scientists from 20 countries. The project took several years to complete.
Ryves noted that saline lakes are present on every continent, but only a handful have undergone thorough study. He called this study “just the tip of the salt berg.” He explained that these lakes support both local wildlife and migrating animals, linking distant ecosystems across very different climates.
He also pointed out that sediment layers over time record changes in a lake’s size and salt levels. This gives scientists a valuable record of past climate shifts, helping them understand how today’s changes compare to natural patterns from history.
