Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UD prof studies how permafrost thawing affects vegetation, carbon cycle

03.03.2016

Study focuses on Toolik Lake area of Alaska's North Slope

Neil Sturchio, professor and chair of the University of Delaware's Department of Geological Sciences, is exploring how the thawing of permafrost, a subsurface layer of soil that remains mostly frozen throughout the year, affects vegetation and the carbon cycle in the Toolik Lake area of the Alaska's North Slope.


University of Delaware snow fence experiment at the Toolik Field Station, North Slope, Alaska.

Credit: University of Delaware

"There is a lot of carbon frozen in the Arctic soil's permafrost layer. If this all thaws out, prevailing thought is that the carbon in the soil could be released to the atmosphere and potentially accelerate global warming," said Sturchio.

Climate models predict 25-50 percent more precipitation in the Arctic region by the end of the century, mostly as fall and winter snow. However, extra snow can also mean extra moisture during warmer seasons like spring and summer.

In 2012, Sturchio and colleagues from several universities conducted a study to determine whether methane and carbon dioxide production in Arctic soils are affected by precipitation, mainly snow accumulation.

Specifically, they studied the long-term effects of projected changes in snow accrual on the methane emissions from moist acidic tundra, which covers over 25 percent of the Alaskan Arctic.

Snow fence experiment

During fieldwork, the scientists used an existing snow fence that had been in place for 18 years to explore what changes in average snow accumulation might mean for the Toolik Lake area. The researchers hypothesized that increased snow accumulation would result in wetter and warmer soils, greater thaw depth and an increase in the abundance of shrubs and tall, grass-like plants called sedges. They also predicted that these soil conditions would lead to increased methane emissions.

Typical winter snowfall depth in the area is about one foot. The snow fence, which stands approximately 9 feet high by 200 feet long, was built perpendicular to the wind direction so that snowdrifts would form behind the fence. This allowed the researchers to mimic various snowfall accumulations for the region, from below normal to average to much higher levels of winter precipitation.

In summer 2012, the researchers established four research plots and took biweekly soil measurements and soil gas samples during the growing season from late May through August. They monitored soil temperature and gas compositions at 10, 20, 35 and 50-centimeter depths; water moisture; oxygen saturation; the amounts and carbon isotope ratios of methane and carbon dioxide; and the thickness of unfrozen ground, known as thaw depth. They also characterized the plant species at peak season.

Snow blanket means longer growing season for plants

As they reviewed the data, the researchers discovered that in areas with increased winter precipitation, the ground didn't freeze as deeply because the snow acted like a blanket, keeping the ground warmer than normal.

Their findings showed that higher snow accumulations resulted in increased soil temperatures and a deeper thawing of the permafrost, which, in turn, resulted in increased microbial activity, increased melting depth and more water content in the soil that led to increased production of methane and more plant growth.

In areas with reduced snow accumulation, however, the soil acted as a methane sink because of enhanced activity of methane-oxidizing bacteria.

The study results suggest that the amount of methane fluctuation was primarily in response to changes in the amount and type of vegetation present, as well as the temperature and moisture of the soil, rather than in how much carbon was in the soil.

When the snow melted, scientists noted a longer growing season for plants and shrubs. In areas with higher snow, the soil also collapsed when the ice that was occupying the soil's pore space melted, causing depressions in the ground.

"It affected more than just the amount of methane produced, it changed the landscape and the types of plants that grew there. We started seeing woody plants -- dwarf trees like birch and other shrubs -- instead of just moss, lichens and grass. This is something you could predict would happen under climate change," Sturchio explained.

More work is needed to better understand the interactions between soil and vegetation processes that affect the release of methane and to determine whether or not the Arctic tundra will act as a significant methane source or methane sink in the future.

"It's safe to say a lot of things are changing in the Arctic. But depending on where you go, the climate change effects are somewhat different," Sturchio said.

The researcher team recently published their findings in the journal Global Change Biology.

###

Co-authors on the work include the paper's lead author Elena Blanc-Betes and the project's principal investigator Miguel Gonzalez-Meler, from University of Illinois at Chicago; Jeffrey Welker from University of Alaska; and Jeffrey Chanton from Florida State University.

This work was funded in part by the Department of Energy, Terrestrial Ecosystem Science Program, and the National Science Foundation.

Peter Bothum | EurekAlert!

More articles from Earth Sciences:

nachricht Geophysicists and atmospheric scientists partner to track typhoons' seismic footprints
16.02.2018 | Princeton University

nachricht NASA finds strongest storms in weakening Tropical Cyclone Sanba
15.02.2018 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

Im Focus: Autonomous 3D scanner supports individual manufacturing processes

Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).

Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Fingerprints of quantum entanglement

16.02.2018 | Information Technology

'Living bandages': NUST MISIS scientists develop biocompatible anti-burn nanofibers

16.02.2018 | Health and Medicine

Hubble sees Neptune's mysterious shrinking storm

16.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>