ANN ARBOR, Mich.---Among the worrisome environmental effects of global warming is the thawing of Arctic permafrost---soil that normally remains at or below the freezing point for at least a two-year period and often much longer. Monitoring changes in permafrost is difficult with current methods, but a study by University of Michigan researchers offers a new approach to assessing the extent of the problem.
The new study approach, which relies on chemical tracers in stream water, is described in the journal Chemical Geology.
Overlying permafrost is a thin "active layer" that thaws every summer, and increases in the thickness of this layer over the years indicate thawing of permafrost. Both physical measurements and modeling suggest that active layer thickness has increased in some areas over the 20th century and that if present warming trends continue, increases of up to 40 percent could occur by the end of the 21st century.
Although the full effects of thawing are yet to be determined, coastal erosion and damage to the roads, buildings and pipelines that have been built on permafrost are likely outcomes. In addition, thawing permafrost may release the greenhouse gases carbon dioxide and methane into the atmosphere, triggering further warming and more permafrost thawing.
Currently, the main method for determining thaw depth is with a graduated steel probe. "You stick it in the ground and see when it hits frozen material," said geochemist Joel Blum, who with ecologist George Kling and former graduate student Katy Keller undertook the new study.
"We were studying the chemistry of soils in the area around Toolik Field Station in northern Alaska, and we found that once we got below the thickness that typically would thaw during summer, the soil chemistry changed dramatically," said Blum, who is the John D. MacArthur Professor of Geological Sciences. "Material that has not thawed since it was deposited by glaciers 10
'/>"/>
| Contact: Nancy Ross-Flanigan rossflan@umich.edu 734-647-1853 University of Michigan Source:Eurekalert |
Related biology news :
1. Volcanic ash research shows how plumes end up in the jet stream
2. New study shows rising water temperatures in US streams and rivers
3. Cold fusion moves closer to mainstream acceptance
4. Study shows woody plant encroachment has increased stream flow in the Edwards Plateau
5. New studies reveal downstream processes of ion channel inactivation
6. How good are tests for E. coli in streams?
7. Chloride found at levels that can harm aquatic life in urban streams of the Northern US
8. Spring cold snap helps with stream ecosystem research
9. Interventional radiology: From sidelines to mainstream for patients
10. Penn medicine draws road map for elimination of central line-associated bloodstream infections
11. GEN reports biomanufacturers target a fully disposable process stream
| Copyright © 2003-2012 Bio-Medicine. All rights reserved. ABOUT | CONTACT US | DISCLAIMER | PRIVACY POLICY | TERMS AND CONDITIONS |  |