Global warming in the Canadian Arctic

November 18, 2013

Ph.D. student Karita Negandhi and professor Isabelle Laurion from INRS'Eau Terre Environnement Research Centre, in collaboration with other Canadian, U.S., and French researchers, have been studying methane emissions produced by thawing permafrost in the Canadian Arctic. These emissions are greatly underestimated in current climate models. Their findings, published in the journal PLOS ONE, illustrate the importance of taking into account greenhouse gases emitted by small thaw ponds, as they could have a significant impact on climate.

"We discovered that although the small shallow ponds we studied represent only 44% of the water-covered surface in a Bylot Island valley, they generate 83% of its ," notes water sciences doctoral student Karita Negandhi.

The researchers compared ponds of different shapes and sizes, and studied their physicochemical properties and microbial ecology. To analyze the samples taken on Bylot Island in Nunavut's Sirmilik National Park, they used various methods, including radiocarbon dating, as well as new-generation molecular tools to study the sediment and water microbial communities involved in carbon transformation processes.

The isotopic signatures of the methane emitted by these small ponds indicate that this comes partly from old carbon reserves that have been sequestered in the for millennia. As the permafrost thaws, organic matter is becoming more abundant, promoting the proliferation of aquatic microbes such as methanogenic Archaea, which use various sources of carbon, then release it into the atmosphere in the form of methane and CO2. Consequently, longer summers could lead to an increase in these emissions.

These small thaw ponds have been studied very little up until now, primarily because of their remote location and the attendant logistical constraints. However in the context of global warming, they are worth examining more closely, as they could have an increasingly significant incidence on the transfer of into the atmosphere in the future.

Explore further: Abrupt permafrost thaw increases climate threat

More information: The article entitled "Small thaw ponds: an unaccounted source of methane in the Canadian High Arctic" appeared in PLOS ONE on November 13, 2013.

Related Stories

Abrupt permafrost thaw increases climate threat

November 30, 2011

As the Arctic warms, greenhouse gases will be released from thawing permafrost faster and at significantly higher levels than previous estimates, according to survey results from 41 international scientists published in the ...

New knowledge about permafrost improving climate models

July 28, 2013

New research findings from the Centre for Permafrost (CENPERM) at the Department of Geosciences and Natural Resource Management, University of Copenhagen, document that permafrost during thawing may result in a substantial ...

Beetles modify emissions of greenhouse gases from cow pats

August 22, 2013

Cattle contribute to global warming by burping and farting large amounts of greenhouse gases. Some of the same gases are also emitted from cow pats on pastures. But now researchers from the University of Helsinki have found ...

The failing freezer: How soil microbes affect global climate

September 24, 2013

The U.S. Department of Energy has awarded $3.9 million to an international collaboration led by University of Arizona ecologists Scott Saleska and Virginia Rich to study how microbes release greenhouse gases as they access ...

Recommended for you

How wind sculpted Earth's largest dust deposit

September 1, 2015

China's Loess Plateau was formed by wind alternately depositing dust or removing dust over the last 2.6 million years, according to a new report from University of Arizona geoscientists.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.