Dust in West up 500 percent in past 2 centuries, says CU-Bou...(er erosion and increased dust deposition...)

Date:2/24/2008

er erosion and increased dust deposition, western U.S. droughts during the past two centuries have been relatively mild compared to droughts over the past 2,000 years, Neff said. Instead, the increased dustiness in the West coincides with intensive land use, primarily grazing, according to radiocarbon dating and lead isotope analysis of soil cores retrieved from lakebeds, he said.

"There were an estimated 40 million head of livestock on the western rangeland during the turn of the century, causing a massive and systematic degradation of the ecosystems," said Neff. The 1934 Taylor Grazing Act that imposed restrictions on western grazing lands coincided with a decrease in accumulation rates of the San Juan lake sediments in the study -- a decrease that continues to today, he said.

The study also shows more than a five-fold increase in nutrients and minerals in the lakebed sediments during the last 150 years, said Neff. Increases in nitrogen, phosphorus, potassium, calcium and magnesium -- byproducts of ranching, mining and agricultural activity - have been shown to change water alkalinity, aquatic productivity and nutrient cycling.

In the Niwot Ridge alpine region west of Boulder, for example, CU-Boulder researchers have observed increased algal growth in streams and lakes as a result of rising nitrogen deposition, as well as changes in the composition and diversity of wildflowers on the tundra. "Because these types of inputs have the potential to increase plant growth, the ultimate outcome of such depositions could change the fabric of our ecosystems," said Neff.

Excessive dust also can cause significant human health problems, including lung tissue damage, allergic reactions and respiratory problems, Neff said.

The San Juan lakes are located in an area dominated by rocky talus slopes with little soil and vegetation at about 13,000 feet in elevation and are located downwind of several major U.S. deserts like the Color
'/>"/>

Contact: Jason Neff Jason.C.Neff@colorado.edu 303-818-4022 University of Colorado at Boulder Source:Eurekalert

0 GOOD

Page: 1 2 3
Related biology news :

1. Nitrogen pollution boosts plant growth in tropics by 20 percent
2. 100 percent of people carry at least 1 type of pesticide
3. Gene, stem cell therapy only needs to be 50 percent effective to create a healthy heart
4. SinuNase Phase 3 show almost 100 percent of chronic sinusitis cases are from fungal-induced inflamma
5. Restless legs syndrome affects nearly 2 percent of US/UK children
6. New study warns limited carbon market puts 20 percent of tropical forest at risk
7. Conservation strategies must shift with global environmental change, says CU-Boulder study
8. CU-Boulder technology used to identify unexpected bacteria in cystic fibrosis patients
9. CU-Boulder worm study sheds light on human aging, inherited diseases
10. Nutrient pollution drives frog deformities by ramping up infections, says CU-Boulder study
11. CU-Boulder team discovers first ancient manioc fields in Americas