The Arctic is getting greener as plant growth increases in response to a warmer climate. This greater plant growth means more carbon is stored in the increasing biomass, so it was previously thought the greening would result in more carbon dioxide being taken up from the atmosphere, thus helping to reduce the rate of global warming.
However, research published in Nature Climate Change, shows that, by stimulating decomposition rates in soils, the expansion of forest into tundra in arctic Sweden could result in the release of carbon dioxide to the atmosphere.
Dr Iain Hartley now based in Geography at the University of Exeter, and lead author of the paper, said: "Determining directly how carbon storage is changing in high-latitude ecosystems is very difficult because the majority of the carbon present is stored below ground in the soils. Our work indicates that greater plant biomass may not always translate into greater carbon storage at the ecosystem level.
"We need to better understand how the anticipated changes in the distribution of different plant communities in the Arctic affects the decomposition of the large carbon stocks in tundra soils if we are to be able to predict how arctic greening will affect carbon dioxide uptake or release in the future."
By measuring carbon stocks in vegetation and soils between tundra and neighbouring birch forest, it was shown that compared to tundra, the two-fold greater carbon storage in plant biomass in the forest was more than outweighed by the smaller carbon stocks in forest soils.
Furthermore, using a novel methodology based on measuring the radiocarbon content of the carbon dioxide being released, the researchers found that the birch trees appeared to be stimulating the decomposition of soil organic matter. Thus, the research was able to identify a mechanism by which the birch trees can contribute directly to reducing carbon storage in soils.
"Dr Gareth Phoenix, of the University of Sheffield's Department Animal and Plant Sciences, who collaborated on the research, added:
"It shows that the encroachment of trees onto Arctic tundra caused by the warming may cause large release of carbon to the atmosphere, which would be bad for global warming.
"This is because tundra soil contains a lot of stored organic matter, due to slow decomposition, but the trees stimulate the decomposition of this material. So, where before we thought trees moving onto tundra would increase carbon storage it seems the opposite may be true. So, more bad news for climate change."
The results of the study are in sharp contrast to the predictions of models which expect total carbon storage to increase with the greater plant growth. Rather, this research suggests that colonisation by productive, high-biomass, plant communities in the Arctic may not always result in greater capture of carbon dioxide, but instead net losses of carbon are possible if the decomposition of the large carbon stocks in Arctic soils are stimulated. This is important as Arctic soils currently store more carbon than is present in the atmosphere as carbon dioxide and thus have considerable potential to affect rates of climate change. It is yet to be seen whether this observed pattern is confined to certain soil conditions and colonising tree species, or whether the carbon stocks in the soils of other arctic or alpine ecosystems may be vulnerable to colonisation by new plant communities as the climate continues to warm.
The research took place within the Natural Environment Research Council (NERC)-funded Arctic Biosphere Atmosphere Coupling at Multiple Scales project (ABACUS; www.abacus-ipy.org) which was led by the University of Edinburgh. This particular study was carried out by a team from the University of Exeter, University of Stirling, NERC Radiocarbon Facility, James Hutton Institute (Aberdeen), the University of Sheffield, and Heriot-Watt University.
About the University of ExeterThe University of Exeter is a leading UK university and in the top one percent of institutions globally. It combines world-class research with very high levels of student satisfaction. Exeter is ranked 9th in The Sunday Times University Guide, 10th in the UK in The Times Good University Guide 2012 and 10th in the Guardian University Guide. In the 2008 Research Assessment Exercise (RAE) 90% of the University's research was rated as being at internationally recognised levels and 16 of its 31 subjects are ranked in the top 10, with 27 subjects ranked in the top 20.
Liz French | EurekAlert!
When corals eat plastics
24.05.2018 | Justus-Liebig-Universität Gießen
Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences