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 team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University
Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
20.11.2017 | Earth Sciences
20.11.2017 | Earth Sciences
20.11.2017 | Life Sciences