Without urgent and major interventions, the United States’ Great Salt Lake could experience ecosystem collapse in the next few years.

In the most pessimistic scenario, according the findings presented at the Geological Society of America’s 2022 Connects Conference in Colorado, the world-renowned saltwater body has just months before ecological recovery is significantly hampered by rising salinity levels.

Water from the rivers that feed Utah’s vast 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 diverted before reaching the lake, mostly for drinking water and agriculture.

Since then, the state has slipped into a megadrought, further reducing the amount of fresh water entering the lake and setting a new record for the lowest water levels ever recorded, it notes Science Alert.

The Great Salt Lake in the US is shrinking

Reports earlier this year estimated that the Great Salt Lake has shrunk by two-thirds since the 1980s, and the dramatic decline is exposing a precious ecosystem on which people, industry and animals collectively depend.

“This is not the kind of record we like to break,” Utah Department of Natural Resources Executive Director Joel Ferry said earlier this year.

“Urgent action is needed to help protect and conserve this critical resource. It’s clear that the lake has problems,” added Ferry at the time.

A unique place

Utah Lake is one of the few places on Earth where mineralized underwater reefs known as microbialites still grow.

These structures look like rocks, but 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, the modern versions of these “living fossils” are rapidly drying up. As underwater microbial mats meet air, they change color from dark green to white. Bleached remains appear to recover only when returned to water of suitable salinity.

The problem is that as the lake shrinks, it becomes more and more concentrated with salt. In 2022, researchers measured salinity levels of up to 26% in some places; a big difference from a more typical lake salinity of about 15%.

Under these extreme conditions, Weber State University biologist Carie Frantz says the recovery of the microbial mat is very poor and slow.

Can the ecosystem recover?

For several summers, Frantz led a team of students to monitor the lake’s microbial life in the field and in the lab to see what happens when bleached reefs are submerged again.

“Last year was really encouraging because I saw that they can bounce back and do it quickly,” she explains.

“This year we saw something very different, we don’t see that clear growth that we saw last year. Organisms are stressed at these salinity levels. The level may be too high for them to grow,” Frantz said.

The Great Salt Lake was “cut” in two

The trend is very similar to what happened in the northern part of the Great Salt Lake following the construction of a levee in the 1950s. A railroad crossing the lake divided the body of water into two parts.

Since the southern portion is mostly fed by fresh water, the northern section has become dangerously salty and oxygen-deprived.

As the salinity reached 25%, a mass die-off of photosynthetic microbes occurred in the lake, resulting in a pink hue that can be seen from space.

What dangers lurk beneath this lake?

The Great Salt Lake is many times saltier than the ocean, and only some microbes can survive in these conditions. Those who can do it are the foundations of the ecosystem, turning sunlight into nutrients for Artemia salina and for saltwater flies and possibly the waterfowl that feed on them.

Dust and mercury pollution could also be a problem in the future if the lake continues to dry up. When a lake in California suffered the same fate, residents suffered far more from asthma and cardiovascular problems.

According to a recent article in The New York Times, the lake bed also contains high levels of arsenic. If the shoreline continues to recede and expose the lake bed to the wind, these poisons may be carried into the lungs of people living nearby.

Drastic measures are needed to protect the Great Salt Lake

Salt Lake City officials have made some attempts to conserve water in the region, but researchers are concerned that those attempts are not keeping pace with climate change or increasing water demand.

Frantz and her team’s findings offer hope only if policymakers take drastic action.

“If the Great Salt Lake recovers soon through a combination of changes in water use and years of high precipitation, the microbial community may be able to recover,” the team writes in the study abstract.

The lake is on the verge of collapse

However, Frantz is concerned that this will not happen. This is an emergency, she says, and as the body of water gets saltier and saltier, it becomes harder and harder for the microbialites to recover.

“We’re not acting fast enough as the situation calls for,” says Frantz.

Bonnie Baxter, professor of biology at Westminster College, shares the concern. She told The New York Times in June that the Great Salt Lake’s ecosystem is on the brink of collapse.

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