The findings, published this week in the online journal, PLoS ONE, are important given the potential for tundra fires to release organic carbon – which could add significantly to the amount of greenhouse gases already blamed for global warming.
Montana State University post-doctoral researcher Philip Higuera is the lead author on the paper, which summarizes a portion of a four-year study funded by the National Science Foundation.
Higuera and his co-authors examined ancient sediments from four lakes in a remote region of Alaska in and around Gates of the Arctic National Park to determine what kind of vegetation existed in the area after the last ice age, 14,000 to 9,000 years ago.
By looking at fossilized pollen grains in the sediment cores, Higuera and his co-authors determined that after the last ice age, the arctic tundra was very different from what it is now. Instead of being covered with grasses, herbs, and short shrubs, it was covered with vast expanses of tall birch shrubs.
Charcoal preserved in the sediment cores also showed evidence that those shrub expanses burned – frequently.
“This was a surprise,” Higuera said. “Modern tundra burns so infrequently that we don’t really have a good idea of how often tundra can burn. Best estimates for the most flammable tundra regions are that it burns once every 250-plus years.”
The ancient sediment cores showed the shrub tundra burned as frequently as modern boreal forests in Alaska – every 140 years on average, but with some fires spaced only 30 years apart.
Higuera’s research is important because other evidence indicates that as the climate has warmed in the past 50 to 100 years, shrubs have expanded across the world’s tundra regions.
“There is evidence of increasing shrub biomass in modern tundra ecosystems, and we expect temperatures to continue to increase and overall moisture levels to decrease. Combine these two factors and it suggests a greater potential for fires,” Higuera said. “The sediment cores indicate that it’s happened before.”
The world’s high latitude tundra and boreal forest ecosystems contain roughly 30 percent of the planet’s total soil carbon. Currently, much of the carbon is locked in permafrost. But a warming climate could cause the permafrost to melt and release its carbon stores into the atmosphere where it would contribute to the greenhouse effect.
“Vegetation change through an increase in shrub biomass and more frequent burning will change a great deal of the carbon cycle in these high latitudes,” Higuera said. “We don’t fully understand the implications, except that it’s reasonable to expect that carbon that was previously locked up could enter the atmosphere.”
The paper is the first in a series Higuera expects to publish from his field work. Future papers will examine how climate, vegetation, and fire regimes have interacted over the past 15,000 years in the region.
Higuera was assisted in his research by MSU undergraduate Alison Kennedy, who graduated in from Earth Sciences in 2007 and co-authors Linda Brubaker and Patricia Anderson from the University of Washington, Thomas Brown from Lawrence Livermore National Laboratory, and Feng Sheng Hu from the University of Illinois. A National Parks Ecological Research Fellow, Higuera works in the Paleoecology Lab led by MSU professor Cathy Whitlock.Contact:
Rebecca Walton | alfa
Scientists on the road to discovering impact of urban road dust
18.01.2018 | University of Alberta
Gran Chaco: Biodiversity at High Risk
17.01.2018 | Humboldt-Universität zu Berlin
Physicists have developed a technique based on optical microscopy that can be used to create images of atoms on the nanoscale. In particular, the new method allows the imaging of quantum dots in a semiconductor chip. Together with colleagues from the University of Bochum, scientists from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute reported the findings in the journal Nature Photonics.
Microscopes allow us to see structures that are otherwise invisible to the human eye. However, conventional optical microscopes cannot be used to image...
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
23.01.2018 | Life Sciences
23.01.2018 | Earth Sciences
23.01.2018 | Physics and Astronomy