The escalation in dust emissions — which may be due to the interplay of several factors, including increased windstorm frequency, drought cycles and changing land-use patterns — has implications both for the areas where the dust is first picked up by the winds and for the places where the dust is put back down.
This image shows a dust storm in Canyonlands National Park.
Credit: Jason Neff
"Dust storms cause a large-scale reorganization of nutrients on the surface of the Earth," said Janice Brahney, who led the study as a CU-Boulder doctoral student. "And we don't routinely monitor dust in most places, which means we don't have a good handle on how the material is moving, when it's moving and where it's going."
Based on anecdotal evidence, such as incidents of dust coating the snowpack in the southern Rockies and a seemingly greater number of dust storms noticed by Western residents, scientists have suspected that dust emissions were increasing. But because dust has not been routinely measured over long periods of time, it was difficult to say for sure.
"What we know is that there are a lot of dust storms, and if you ask people on the Western Slope of Colorado, or in Utah or Arizona, you'll often hear them say, 'Yeah, I grew up in this area, and I don't remember it ever being like this before,'" said CU-Boulder geological sciences Associate Professor Jason Neff, Brahney's adviser and a co-author of the paper. "So there is anecdotal evidence out there that things are changing, but no scientific data that can tell us whether or not that's true, at least for the recent past."
For the new study, recently published online in the journal Aeolian Research, the research team set out to determine if they could use calcium deposition as a proxy for dust measurements. Calcium can make its way into the atmosphere — before falling back to earth along with precipitation — through a number of avenues, including coal-fired power plants, forest fires, ocean spray and, key to this study, wind erosion of soils.
The amount of calcium dissolved in precipitation has long been measured by the National Atmospheric Deposition Program, or NADP, which first began recording the chemicals dissolved in precipitation in the late 1970s to better understand the phenomena of acid rain.
Brahney and her colleagues reviewed calcium deposition data from 175 NADP sites across the United States between 1994 and 2010, and they found that calcium deposition had increased at 116 of them. The sites with the greatest increases were clustered in the Northwest, the Midwest and the Intermountain West, with Colorado, Wyoming and Utah seeing especially large increases.
The scientists were able to determine that the increase was linked to dust erosion because none of the other possible sources of atmospheric calcium — including industrial emissions, forest fires or ocean spray — had increased during the 17-year period studied.
It's also likely that the calcium deposition record underrepresents the amount of dust that's being blown around, said Brahney, who is now a postdoctoral researcher at the University of British Columbia in Canada. That's because the NADP network only measures dust that has collided with water in the atmosphere before precipitating to earth — not dust that is simply moved by the wind. And not all dust contains the same amount of calcium.
The increase in dust erosion matters, the researchers said, because it can impoverish the soil in the areas where dust is being lost. Wind tends to pick up the finer particles in the soils, and those are the same particles that have the most nutrients and can hold onto the most soil moisture, Brahney said.
Increasing amounts of dust in the atmosphere also can cause people living in the rural West a variety of problems, including poor air quality and low visibility. In extreme cases, dust storms have shut down freeways, creating problems for travelers.
The areas where the dust travels to are also affected, though the impacts are more mixed. When dust is blown onto an existing snowpack, as is often the case in the Rockies, the dark particles better absorb the sun's energy and cause the snowpack to melt more quickly. But the dust that's blown in also brings nutrients to alpine areas, and the calcium in dust can buffer the effects of acid rain.
In the future, researchers working in Neff's lab hope to get a more precise picture of dust movement by measuring the dust itself. In the last five years, large vacuum-like measuring instruments designed specifically to suck in dust emissions have been installed at sites between the canyon lands of Utah and the Front Range of the Rockies. Once scientists have enough data collected, they'll be able to look for trends in dust emissions without relying on proxies.
The study was funded by the National Science Foundation.
Jason Neff | EurekAlert!
Sea ice extent sinks to record lows at both poles
23.03.2017 | NASA/Goddard Space Flight Center
Less radiation in inner Van Allen belt than previously believed
21.03.2017 | DOE/Los Alamos National Laboratory
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
23.03.2017 | Life Sciences
23.03.2017 | Power and Electrical Engineering
23.03.2017 | Earth Sciences