Particles from U.S. Dust Storms of the 1930s May Have Traveled as Far as Greenland, UB Research Shows

BUFFALO, N.Y. -- Specks of dust may have traveled from America's Great Plains all the way to Greenland in the Arctic Region during the Dust Bowl storms of the 1930s, according to new findings by atmospheric physicists at the University at Buffalo.

The research, published in Geophysical Research Letters on March 18, adds evidence to a hypothesis proposed in the 1970s that ice cores from Greenland may contain dust from the "black blizzards" of the Great Plains that occurred in the 1930s.

It indicates that the central United States may be a significant contributor of dust to the Greenland ice sheet, particularly in periods of severe drought.

"Unfortunately, dust particles, which we study in microgram amounts, don't come with labels that say 'made in the USA'," said Michael Ram, Ph.D., professor of physics in the UB College of Arts and Sciences and co-author on the paper.

First author on the paper is John Donarummo, Jr., a doctoral candidate in the UB Department of Physics.

Scientists study ice cores from Greenland because they serve as a frozen archive recording historic climate details, including atmospheric dust concentrations.

"We have to analyze the chemical composition of the dust and in this case, the clay composition was consistent with dust from the central U.S.," Ram explained.

Nevertheless, he said, because other arid climates, such as the Sahara desert, also produce dust with similar chemical compositions, additional evidence was needed.

Drawing on ice cores retrieved through the Greenland Ice Sheet Project 2, the UB scientists used laser-light scattering techniques to determine changes in dust concentration along the core.

When laser light is directed at an ice-core melt-water sample, dust in the sample scatters the light, producing a pattern of peaks and valleys along the core that correspond to seasonal dust changes.

"When we looked at this one peak, it stood out quite dramatically," explained Ram. "Because we have dated this ice core very precisely, we knew that this dust peak corresponded to either 1933 or late 1933, early 1934."

With approximately 38 dust storms recorded in the Great Plains, 1933 was the first of the worst years of the Dust Bowl period.

The dust sample also contained more large particles in it than most dust samples retrieved from ice cores, Ram said, a likely indication that it had not traveled as far as some other samples that most likely originated in Asia.

In addition, the scientists identified in the sample numerous diatoms, microscopic single-celled aquatic plants that also inhabit shallow water bodies and soils and that are consistent with diatoms found in the central U.S.

"Some scientists have concluded that the main source of dust in the GISP2 ice core is Asia, based on its mineralogy and isotopic signature," said Ram. "What we are saying is that under certain atmospheric circumstances, the central U.S. can also contribute dust to this ice core."

E.F. Stoermer from the Herbarium at the University of Michigan, who identified the diatoms found in the dust, is a co-author.

The work was funded by the National Science Foundation.