Utah’s Great Salt Lake is the smallest and saltiest lake in recorded history. In July, the United States Geological Survey (USGS) reported that her third-largest saline lake in the world had dropped to the lowest level ever recorded. And last week, researchers measured the highest salinity ever seen in the southern arm of the lake, an important bird habitat. beyond the threshold to start

The trend, caused by drought and water diversion, has led scientists to warn that critical feeding grounds for millions of migratory birds are at risk of collapse.

“We are obsessed with uncharted waters,” said Bonnie Baxter, a biochemist at the University of Westminster who has documented the lake’s astonishing changes. The next week we see dead flies along the shore, and every week we have to walk further to reach the water.”

After years of inaction, the prospect that the lake is dying, coupled with the danger of toxic dust being blown from the dry lake bed, has prompted policy makers to find ways to bring water back to the shrinking lake. I am trying to find the.

The Great Salt Lake is actually two lakes, separated by a railroad causeway in 1959. Over time, the northern bank, with few freshwater sources, became more saline than the southern bank, which was fed by three rivers. Historically, the northern arm has hovered around 32% salinity (too salty to support more than microbes) and the southern arm around 14%.

The South contains about four times the salinity of sea water, yet supports a vibrant ecosystem featuring billions of brine shrimp and brine flies that feed on photosynthetic cyanobacteria and other microorganisms. . When birds arrive at lakes to nest, molt, or rest while migrating, they devour vast numbers of flies and shrimps. For example, diving waterfowl called eared grebes require 28,000 adult brine shrimp daily to survive.

Falling water levels and rising salinity threaten to destroy the foundation of this food web, researchers say. Receding shorelines have already dried out many reef-like mats of cyanobacteria, known as microbes, that dot the bottom of lakes. Baxter worries that even the microbial communities that remain submerged are threatened by the increased salinity of seawater: “In laboratory tests, salinity levels above 17% have shown that cyano her I found that the bacteria started to die off,” she says.

Baxter said the loss of the mat could compromise the brine fly population. Flies lay their eggs on the surface of the lake, produce larvae, and descend to microorganisms, where they pupate before becoming adults. Some birds eat larvae and adults, while others eat pupae. Pupa are dying in the billions on lake shores this fall migration season.

Brine shrimp may also decline soon. “I fear that in a future year, [the lake] Salinity will rise and the population will … collapse,” two state ecologists recently wrote.

Meanwhile, researchers are mobilizing to track the unfolding crisis. Baxter has brought in his fly expert Brine to assess the situation. Conservation groups track shorebird populations in the western mountains. The USGS has also established programs to monitor hydrology and ecology at other salt lakes in Oregon, California, Nevada, and Utah facing similar stresses.

Shrinking lakes pose a threat to wildlife as well as people. In his 2019 state-funded report, Kevin Perry, an atmospheric scientist at the University of Utah, believes that 9% of his exposed lake sediments come from industry, wastewater treatment, or agriculture. I presumed it contained problematic levels of arsenic or metals. Winds can erode the crust that holds sediments and carry dust far. The scenario is an air pollution disaster, similar to that experienced by other Iranian communities near salt lakes. Even Utah’s famous ski resorts are at risk from dust. Scientists have documented how storms are already dumping lake bed particles onto the snow, darkening it and hastening its melting.

For years, conservationists have urged policy makers to divert less water from the streams that feed the lake by farmers and other users. But “conventional wisdom was that it was just a salty lake. You’d have to use upstream water,” says Utah Representative Tim Hawkes. “For many people in Utah, the lake was a little out of sight and out of their minds.”

But this year, policymakers took action. In April, Utah Governor Spencer Cox signed a landmark series of bills aimed at saving the lake and combating drought. This includes new rules that allow farmers to sell unused water rights to groups that allow water to flow into the lake. The state has earmarked his $450 million for water infrastructure and conservation projects, including his $40 million fund that could acquire the lake’s water in the future.

It could take years for such policies to have a noticeable impact, especially if the current drought persists. Baxter, for example, asks, “Is this good enough?” But Marcel Shupe, who heads the salt lake program at the National Audubon Society, said, “I’m optimistic because there are so many people trying to develop a solution.”

In the meantime, the lake may be temporarily relieved from another cause. It is the coming winter rainy season. If there is good snowpack in the nearby mountains, runoff water could help replenish dry streams in the area.