Warmer air temperatures since the 1980s may explain significant increases in zinc and other metal concentrations of ecological concern in a Rocky Mountain watershed, reports a new study led by the U.S. Geological Survey and the University of Colorado Boulder.
Rising concentrations of zinc and other metals in the upper Snake River just west of the Continental Divide near Keystone, Colo., may be the result of falling water tables, melting permafrost and accelerating mineral weathering rates, all driven by warmer air temperatures in the watershed. Researchers observed a fourfold increase in dissolved zinc over the last 30 years during the month of September.
Increases in metals were seen in other months as well, with lesser increases seen during the high-flow snowmelt period. During the study period, local mean annual and mean summer air temperatures increased at a rate of 0.5 to 2.2 degrees Fahrenheit per decade.
Generally, high concentrations of dissolved metals in the Snake River watershed are primarily the result of acid rock drainage, or ARD, formed by natural weathering of pyrite and other metal-rich sulfide minerals in the bedrock. Weathering of pyrite forms sulfuric acid through a series of chemical reactions, and pulls metals like zinc from minerals in the rock and carries these metals into streams.
Increased sulfate and calcium concentrations observed over the study period lend weight to the hypothesis that the increased zinc concentrations are due to acceleration of pyrite weathering. The potential for comparable increases in metals in similar Western watersheds is a concern because of impacts on water resources, fisheries and stream ecosystems. Trout populations in the lower Snake River, for example, appear to be limited by the metal concentrations in the water, said USGS research biologist Andrew Todd, lead researcher on the project.
"Acid rock drainage is a significant water quality problem facing much
'/>"/>
| Contact: Diane McKnight Diane.McKnight@colorado.edu 303-492-4687 University of Colorado at Boulder Source:Eurekalert |
Related biology news :
1. Increase in Arctic shipping poses risk to marine mammals
2. Columbia Engineering and Penn researchers increase speed of single-molecule measurements
3. Fertilizer use responsible for increase in nitrous oxide in atmosphere
4. NIST/UMass study finds evidence nanoparticles may increase plant DNA damage
5. Study finds soda consumption increases overall stroke risk
6. Scientists have discovered genes that increase the risk of osteoporosis and fractures
7. Family history of liver cancer increases risk of developing the disease
8. Research shows how PCBs promote dendrite growth, may increase autism risk
9. Increased fructose consumption may deplete cellular energy in patients with obesity and diabetes
10. NIH-led study finds genetic test results do not trigger increased use of health services
11. Flapping protective wings increase lift
| Copyright © 2003-2012 Bio-Medicine. All rights reserved. ABOUT | CONTACT US | DISCLAIMER | PRIVACY POLICY | TERMS AND CONDITIONS |  |