Navigation Links
Stream water study detects thawing permafrost
Date:5/5/2010

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 10,000 to 20,000 years ago is now beginning to thaw, and when it does, it reacts strongly with water, which it's encountering for the first time. This soil is much more reactive than soils higher up that interact with soil water every summer."

In particular, the amount of calcium, relative to sodium and barium, is higher in the newly-thawed permafrost, and the ratio of the strontium isotope 87Sr to its counterpart 86Sr is lower. The researchers wondered if these chemical signatures of increasing thaw depth could be seen in local stream water.

Kling, who is the Robert G. Wetzel Collegiate Professor of Ecology and Evolutionary Biology, has conducted research at Toolik Lake for many years and obtained stream water samples that had been collected over an 11-year period.

When the samples were analyzed, "we saw really significant changes from year to year that were consistent with what you would predict from increasing thaw depth," Kling said.

Although the method can't reveal precisely how much permafrost thawing is occurring in particular localities, it still can be a useful adjunct to current methods, Blum said. "We'd love to be able to say that we see an increase in thickness of, say, 1 centimeter over the entire watershed, but we simply can't say where in the watershed thawing is occurring. Nevertheless, we think it's important to monitor streams in Arctic regions to keep track of these kinds of changes and follow the rate of change."


'/>"/>

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
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/5/2017)... KEY FINDINGS The global market for stem ... 25.76% during the forecast period of 2017-2025. The rise ... growth of the stem cell market. Download ... The global stem cell market is segmented on the ... cell market of the product is segmented into adult ...
(Date:4/3/2017)... April 3, 2017  Data captured by ... platform, detected a statistically significant association between ... to treatment and objective response of cancer ... to predict whether cancer patients will respond ... as well as to improve both pre-infusion potency ...
(Date:3/30/2017)... 2017 The research team of The Hong ... fingerprint identification by adopting ground breaking 3D fingerprint minutiae recovery and ... speed and accuracy for use in identification, crime investigation, immigration control, ... ... A research team led ...
Breaking Biology News(10 mins):
(Date:8/21/2017)... ... August 21, 2017 , ... Baltimore ... bio security firm, to bring its proprietary CANARY pathogen detection technology and high ... the Chinese firm has purchased an undisclosed number of PathSensors’ Zephyr pathogen detection ...
(Date:8/18/2017)... ... August 18, 2017 , ... ... the Semiconductor, MEMS, and Microfluidics Industries, announces the new Model 800E front and ... often in automated production mask aligners. OAI has already received and installed ...
(Date:8/16/2017)... Yorba Linda, Ca (PRWEB) , ... August 16, ... ... resist treatment by changing into a different cell type. Many treatments for specific ... tissue. A prominent example of targeted treatment is androgen deprivation therapy for advanced ...
(Date:8/16/2017)... and OXFORD, England , Aug. 16, 2017 ... for biotech executive search and leadership development, and Virdis Group, ... have created an exclusive alliance that enables clients to leverage ... "For our clients here in the ... access to a diverse population of leadership talent throughout the ...
Breaking Biology Technology: