Without urgent and significant interventions, America’s Great Salt Lake could experience ecosystem collapse in the coming years.
In a worst-case scenario, according to findings presented at the Geological Society of America’s 2022 Connects conference in Colorado last weekend, the world-famous saltwater body has just months before its ecological recovery from rising salinity levels is significantly hampered.
Water from the rivers that feed into Utah’s massive lake has been diverted for human consumption for more than a century. A 2017 study estimated that each year a total of 3.3 trillion liters of water is rerouted before reaching the lake, mostly for drinking water and agriculture.
Since then, the state has slipped into a major drought, further reducing the amount of fresh water entering the lake and setting a new record for the lowest water levels ever recorded.
Reports from earlier this year estimate that the Great Salt Lake has shrunk by two-thirds since the 1980s, and the dramatic decline is exposing a valuable ecosystem on which people, industry and animals collectively depend.
“This is not the type of record we like to break,” Utah Department of Natural Resources Executive Director Joel Ferry said earlier this year.
“Urgent action is needed to protect and conserve this critical resource. It is clear the lake is in trouble.”
Utah Lake is one of the very few places on Earth where mineralized submarine reefs known as microbialites still grow.
These structures may look like rocks, but they are actually dense concentrations of algae and bacteria. In fossil form, they are known as stromatolites and are considered the oldest evidence of life on Earth.
As water levels in the Great Salt Lake continue to drop, modern versions of these “living fossils” are quickly drying up. As the underwater microbial mats meet the air, they turn from dark green to white. The bleached remains seem to be recovering only when returned to water of suitable salinity.
The problem is that as the Great Salt Pan shrinks, it becomes more and more concentrated with salt. In 2022, researchers measured salinity levels as high as 26 percent in some spots. a huge difference to a more typical lake salinity of about 15 percent.
Under these extreme conditions, biologist Carie Frantz of Weber State University says the recovery of the microbial layer is very weak and slow.
For several summers now, Frantz has led a team of undergraduate students to monitor the lake’s microbial elements in the field and in the lab to see what happens when the bleached reefs are submerged again.
“Last year was really encouraging, because we saw that they can come back and they come back quickly,” he explains.
“This year we saw something very different, we don’t see that clear increase that we saw last year. Organisms are stressed at these salinity levels. It’s likely to be too high to grow.”
The trend is very similar to what happened in the northern part of the Great Salt Lake after a boardwalk was built in the 1950s. This railroad crossing the lake divided the body of water into two parts.
Because the southern part is fed mostly by fresh water, the northern part became dangerously salty and deprived of oxygen.
As the salinity reached 25 percent, a mass extinction of photosynthetic microbes occurred in the lake, causing a pink hue that can be seen from space.
The Great Salt Lake is many times saltier than the ocean and only a few microbes can survive in these conditions. Those that can do so are the foundation of the ecosystem, turning sunlight into nutrients for brine shrimp and flies and ultimately for the waterfowl that feed on them.
Powder and mercury pollution it could also be a problem in the future if the lake continues to dry up. When a lake in California suffered the same fate, local residents he suffered much more from asthma and cardiovascular problems.
According to a recent report by The New York Times, the lake bed also contains high levels of arsenic. If the shoreline continues to recede and expose the lake bottom to the wind, it is possible that these poisons will be carried into the lungs of people living nearby.
Salt Lake City lawmakers have made some efforts to conserve water in the area, but researchers worry that these changes are not keeping pace with climate change or increasing water demands.
Frantz and her team’s findings are only promising if policymakers take drastic action.
“[If] the Great Salt Lake will soon recover from some combination of societal changes in water use and years of high precipitation, the microbial community may be able to recover,” the team writes in its abstract.
Frantz, however, worries that won’t happen. This is an emergency situation, he says, and as the body of water gets saltier and saltier, it becomes harder and harder for the microbes to recover.
“We are not acting as quickly as the situation requires,” Frantz says in a recent GSA press release.
Bonnie Baxter, professor of biology at Westminster College, shares the concern. She said The New York Times in June that the Great Salt Lake ecosystem is on the brink of collapse.