Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Burning Northern Wetlands Release Increased Quantities of Sequestered Mercury

21.08.2006
Climate change appears to be contributing to the waking of a toxic sleeping giant in the most northern wetlands of North America. Mercury, released into the atmosphere most prodigiously with the launching of the industrial age, falls back onto Earth and accumulates, particularly in North American wetlands.

Researchers at Michigan State University, the U.S. Geological Survey, the National Center for Atmospheric Research, and the Canadian Forest Service find that wildfires, which are becoming more frequent and intense, are unleashing this sequestered mercury at levels up to 15 times greater than previously calculated. Their report was published 19 August in Geophysical Research Letters.

"This study makes the point that while peat lands are typically viewed as very wet and stagnant places, they do burn in continental regions, especially late in the season when water tables are depressed," said Merritt Turetsky, lead author of the study. "When peat lands burn, they can release a huge amount of mercury that overwhelms regional atmospheric emissions. Our study is new in that it looks to the soil record to tell us what happens when peat soil burns, soil that has been like a sponge for mercury for a long time."

Normal atmospheric conditions naturally carry the mercury emitted from burning fossil fuel and other industry northward, where it eventually settles on land or water surfaces. The cold, wet soils of the boreal forest region in Alaska and northern Canada have been efficient in retaining, or sequestering, mercury.

"When we walk across the surface of a peat land, we are standing on many thousands of years of peat accumulation," Turetsky said. "This type of wetland is actually doing us a service. Peat lands have been storing mercury from the atmosphere since well before and during the Industrial Revolution, locking it in peat where it's not causing any biological harm, away from the food web."

In addition to industrial activity, climate change also appears to be disrupting the mercury cycle. Increasingly, northern wetlands are drying out. Forest fires are burning more frequently, more intensely, and later in the season, which Turetsky believes will make peat lands more vulnerable to fire. In May, Turetsky co-authored with Eric Kasischke of the University of Maryland another Geophysical Research Letters paper that documented recent changes in North American fires and proposed that more frequent summer droughts and severe fire weather have increased burn areas.

"We are suggesting that environmental mercury is just like a thermometer. Levels will rise in the atmosphere with climate change, but due to increasing fire activity in the north and not solely due to warming, said Jennifer Harden, soil scientist at the U.S. Geological Survey and a co-author of the study.

In the newly published paper, Turetsky and her co-authors measured the amount of mercury stored in soils and vegetation of forests and peat lands, then used historical burn areas and emission models to estimate how much of that mercury is released to the atmosphere at a regional scale during fires.

The group studied more than five years of prescribed burns and natural fires to measure the influence of burning on terrestrial mercury storage. They also sampled smoke plumes to measure atmospheric mercury levels as fires blaze.

Their findings indicate that drier conditions in northern regions will cause soil to relinquish its hold on hundreds of years of mercury accumulation, sending that mercury back into the air at levels considerably higher than previously realized.

We're talking about mercury that has been relatively harmless, trapped in peat for hundreds of years, rapidly being spewed back into the air," Turetsky said. "Some of it will fall back onto soils. Some will fall into lakes and streams where it could become toxic in food chains. Our findings show us that climate change is complex and will contribute to the pollution of food chains that are very far away from us, in remote regions of the north."

The research was funded by the U.S. Geological Survey, the National Center of Atmospheric Research (supported by the National Science Foundation), and the Electric Power Research Institute. Turetsky's work also is supported by Michigan State University's Michigan Agricultural Research Station.

Harvey Leifert | AGU
Further information:
http://www.agu.org

More articles from Earth Sciences:

nachricht NASA looks to solar eclipse to help understand Earth's energy system
21.07.2017 | NASA/Goddard Space Flight Center

nachricht Scientists shed light on carbon's descent into the deep Earth
19.07.2017 | European Synchrotron Radiation Facility

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

Ultrathin device harvests electricity from human motion

24.07.2017 | Power and Electrical Engineering

Scientists announce the quest for high-index materials

24.07.2017 | Materials Sciences

ADIR Project: Lasers Recover Valuable Materials

24.07.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>