Determining Dust Impacts on Great Basin National Park

This article was originally published in The Midden - Great Basin National Park: Vol 24., No.1, Summer 2024.

The passive dust collector in the Wheeler Peak area has five troughs with V-shaped cross sections filled with black glass marbles. In the background, a dust storm arises from Yelland Dry Lakebed and transports it to the east to the North Snake Range.

J. Munroe

By Jeff Munroe, Researcher, Middlebury College

How does the emission, transport, and deposition of mineral dust impact the Critical Zone in downwind mountain ecosystems? The US National Science Foundation awarded funding to study this, with a network of passive dust samplers developed across the Intermountain West and Great Basin. A passive dust collector was installed near Wheeler Peak in 2020 to collect dry dust that falls out of the air naturally and wet dust that is washed out of the air by rain or snow.

Great Basin National Park is an important study area because the Park is located in the middle between desert dust source areas in southern Nevada and extensively studied sites of dust deposition in the mountains of northern Utah. Also, the protected environment of the Park means the dust can be sampled in as natural setting as possible. The site is also relatively easy to access, with a paved road leading up to the Wheeler Peak Campground.

The amount of dust deposition varies slightly from year to year and is also typically higher in the summer. The overall average depositional rate is 1.3 grams per square meter each year, which doesn’t seem like much. But when extrapolated, this equals 4 pounds of mineral dust landing annually on each acre of the mountain landscape. Clearly this can be a big deal when continued over years and years.

Two major projects have been completed so far using results from this dust collector, along with others deployed elsewhere in the region. In the first project, colleagues and I discovered that the physical and chemical properties of the dust vary to a surprising degree from one mountain range to another. The extent of this variability was surprising because previous work had assumed that dust in the air was well-mixed and homogenous – meaning that the same type of dust would fall just about everywhere. Our results reveal that the dust is really different in different locations, a result that indicates that much of the dust is actually derived from the arid lowlands in the area immediately surrounding each collector. Different geology in these areas means different dust arriving in the nearby mountains.

In the second project, we investigated how the formation of mountain soils is impacted by dust deposition. We found that these soils are profoundly influenced by dust – indeed, in some cases, nearly 100% of the soil wouldn’t be there at all without slow dust deposition over time! Soils are obviously a critical foundation for ecosystems, so the realization that mountain soils wouldn’t be what they are without dust has important implications.

Two other projects are currently in progress. In one, the dust from this and other collectors in the Great Basin is being compared with “urban” dust along the Wasatch Front in northern Utah to see how human activity in the city changes the properties of natural dust (and to figure out how that urban-influenced dust impacts downwind mountain ranges). And in the second project, summer vs. winter dust is being compared to see how depositional rates and dust properties vary in different seasons.Check out these articles to learn even more about dust deposition in Great Basin National Park and the surrounding area.

Munroe, J. S., Soderstrom, E. J., Kluetmeier, C. L., Tappa, M. J., Mallia, D. V., & Bauer, A. M. (2023). Regional sources control dust in the mountain critical zone of the Great Basin and Rocky Mountains, USA. Environmental Research Letters, 18(10), 104034. https://iopscience.iop.org/article/10.1088/1748-9326/acfb26

Munroe, J. S., Santis, A. A., Soderstrom, E. J., Tappa, M. J., & Bauer, A. M. (2024). Mineral dust and pedogenesis in the alpine critical zone. SOIL, 10(1), 167-187. soil.copernicus.org/articles/10/167/2024/soil-10-167-2024.pdf