Polluted dust linked to troubling changes in mountain lakes

SALT LAKE CITY (ABC4) — Dust isn’t the same as it always was.

Modern dust contains fertilizers, pesticides and tiny plastics, said Janice Brahney, an associate professor with Utah State University’s Department of Watershed Sciences.

“What we would have thought of as what’s typically in dust is different now than it was 150 years ago,” she said, explaining that these complex compounds and materials come from agricultural sources, urban areas and industry.

Brahney leads a team of researchers who’ve recently published a study about how atmospheric dust is affecting mountain headwaters across the world. This research was the product of 15 years of work.

What the research showed is that this nutrient-rich dust can spur algae growth when it’s blown into bodies of water in remote mountain areas.

While this growth might be a positive for some ecosystems as global warming makes lakes warmer and more acidic, too much growth could be detrimental, as it could lead to toxic algae blooms.

In mountain lake ecosystems, these toxic blooms threaten to disrupt the delicate balance that exist between animals and their environment, with impacts up the food chain. In the last two years, a number of toxic algal blooms have happened in alpine lakes in Wyoming’s Wind River Range.

“Only recently have we started to see troubling outbreaks of toxic algal blooms in mountain environments,” Brahney said, in a statement. “So these changes are happening fast and are really concerning.”

Her team launched the first-ever dust monitoring program across the Western United States, with 30 locations spread across the region. This has allowed them to run experiments on how dust, temperature and acidity in lakes affect algal growth rates.

The researchers used this data to map out potential effects on mountain headwaters across the world, specifying high risk areas. These include the Tibetan Plateau, southern Africa, central Australia, and the Western U.S.

Ben Abbott, an associate professor of environmental science and sustainability at Brigham Young University, said the research is important because so much is currently changing with the earth’s systems.

“We have climate change and land use change, changes to the atmospheric deposition of dust, all of that is happening at the same time, and it’s really important to consider interactions among those drivers,” he said.

Abbott, who was not involved with the study, said that most water bodies across the U.S. are currently experiencing over-fertilization. The consequences of dust storms dropping more nutrients into these lakes makes it so that algal blooms could become more intense and last longer.

Mountain headwaters are significant because they supply roughly half the world’s population with fresh drinking water, irrigation, and industry, Brahney said. They are also areas of cultural and recreational significance, particularly in Utah.

“These systems are really important to us from all kinds of different angles,” Brahney said.

As for how the dust is traveling to these lakes, research has shown that much of it is shot into the air on freeways. Friction from the tires kicks the particles high into the atmosphere, from which they can be carried thousands of miles on the wind.

Looking ahead, Brahney and her team are planning to trace where the dominant sources of dust in the American West are coming from. She hopes this work could perhaps lead to better policies for effective land use.