Preliminary assessments by scientists from Russia, the University of Florida, and the University of Alaska Fairbanks indicate that loess permafrost, which covers more than a million square kilometers in Siberia and Alaska, is a large carbon reservoir with the potential to be a significant contributor of atmospheric carbon, yet it is seldom incorporated into analyses of changes in global carbon reservoirs.
“The unique aspect of the Siberian loess permafrost is that it is quite deep – 20 to 40 meters - and has a surprisingly high carbon concentration at depth for a mineral soil,” said Terry Chapin, co-author from the Institute of Arctic Biology at UAF. “This paper explains the processes that led to the accumulation of large amounts of soil carbon and the processes that could lead to its return to the atmosphere.”
The largest carbon reservoir on Earth is the ocean, which scientists estimate holds about 40,000 gigatons; soils contain about 2,500 Gt and vegetation about 650 Gt. According to the authors, about 500 Gt of carbon are contained in the thaw-threatened loess, also called yedoma, of Siberia and Alaska.
“I was surprised, because it is unusual to find major new large carbon stocks,” Chapin said. “We have spent more than five years discussing among ourselves all the details of the calculations, because initially I did not believe that the pool could be both so large and so decomposible (once thawed).”
Permafrost has been seldom incorporated into global carbon budgets in part because the “... size of the carbon pool was so poorly quantified ... and in part because global data bases for soils have been standardized to provide data only for the top meter of soil,” Chapin said. “People know about carbon in permafrost - it’s not a trivial amount,” said Ted Schuur, co-author from the University of Florida. “Normally, scientists look for carbon in the upper layers of permafrost where organic matter decomposes.”
Laboratory and field experiments by the scientists demonstrate that the organic matter in yedoma decomposes quickly when it is thawed and produces rates of carbon release similar to those of productive northern grassland soils. “If these rates continue as field observations suggest, most carbon in recently thawed yedoma will be released within a century - a striking contrast to the preservation of carbon for tens of thousands of years when frozen in permafrost,” state the authors.
The National Science Foundation provided financial support for this research.
Marie Gilbert | EurekAlert!
Thawing permafrost produces more methane than expected
20.03.2018 | GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre
Wandering greenhouse gas
16.03.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...
The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
20.03.2018 | Physics and Astronomy
20.03.2018 | Physics and Astronomy
20.03.2018 | Earth Sciences