Climate feedbacks from decomposition by soil microbes are one of the biggest uncertainties facing climate modelers.
A new study from the International Institute for Applied Systems Analysis (IIASA) and the University of Vienna shows that these feedbacks may be less dire than previously thought.
The dynamics among soil microbes allow them to work more efficiently and flexibly as they break down organic matter – spewing less carbon dioxide into the atmosphere than previously thought, according to a new study published in the journal Ecology Letters.
"Previous climate models had simply looked at soil microbes as a black box," says Christina Kaiser, lead author of the study who conducted the work as a post-doctoral researcher at IIASA. Kaiser, now an assistant professor at the University of Vienna, developed an innovative model that helps bring these microbial processes to light.
Microbes and the climate
"Soil microbes are responsible for one of the largest carbon dioxide emissions on the planet, about six times higher than from fossil fuel burning," says IIASA researcher Oskar Franklin, one of the study co-authors. These microbes release greenhouse gases such as carbon dioxide and methane into the atmosphere as they decompose organic matter. At the same time, the Earth's trees and other plants remove about the same amount of carbon dioxide from the atmosphere through photosynthesis.
As long as these two fluxes remain balanced, everything is fine.
But as the temperature warms, soil conditions change and decomposition may change. And previous models of soil decomposition suggest that nutrient imbalances such as nitrogen deficiency would lead to increased carbon emissions. "This is such a big flux that even small changes could have a large effect," says Kaiser. "The potential feedback effects are considerably high and difficult to predict."
Diversity does the trick
How exactly microorganisms in the soil and litter react to changing conditions, however, remains unclear. One reason is that soil microbes live in diverse, complex communities, where they interact with each other and rely on one another for breaking down organic matter.
"One microbe species by itself might not be able to break down a complex substrate like a dead leaf," says Kaiser. "How this system reacts to changes in the environment doesn't depend just on the individual microbes, but rather on the changes to the numbers and interactions of microbe species within the soil community."
To understand these community processes, Kaiser and colleagues developed a computer model that can simulate complex soil dynamics. The model simulates the interactions between 10,000 individual microbes within a 1mm by 1mm square. It shows how nutrients, which influence microbial metabolism, affect these interactions, and change the soil community and thereby the decomposition process.
Previous models had viewed soil decomposition as a single process, and assumed that nutrient imbalances would lead to less efficient decomposition and hence greater greenhouse gas emissions. But the new study shows that, in fact, microbial communities reorganize themselves and continue operating efficiently – emitting far less carbon dioxide than previously predicted.
"Our analyses highlight how the systems thinking for which IIASA is renowned advances insights into key ecosystem services," says study co-author and IIASA ecologist Ulf Dieckmann.
"This model is a huge step forward in our understanding of microbial decomposition, and provides us with a much clearer picture of the soil system," says University of Vienna ecologist Andreas Richter, another study co-author.
Kaiser C, Franklin O, Dieckmann U, and Richter A. 2014. Microbial community dynamics alleviate stoichiometric constraints during litter decay. Ecology Letters. http://onlinelibrary.wiley.com/doi/10.1111/ele.12269/abstract
For more information please contact:
University of Vienna
Department of Microbiology and Ecosystem Science
Tel: +43 (0)1 4277 76663
Mob: +43 6503773428
Ecosystems Services and Management
+43(0) 2236 807 251
IIASA is an international scientific institute that conducts research into the critical issues of global environmental, economic, technological, and social change that we face in the twenty-first century. Our findings provide valuable options to policy makers to shape the future of our changing world. IIASA is independent and funded by scientific institutions in Africa, the Americas, Asia, Oceania, and Europe. http://www.iiasa.ac.at
Katherine Leitzell | EurekAlert!
Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main
Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy