Climate warming may not drive net losses of soil carbon from tropical forests
The planet's soil releases about 60 billion tons of carbon into the atmosphere each year, which is far more than that released by burning fossil fuels. This happens through a process called soil respiration. This enormous release of carbon is balanced by carbon coming into the soil system from falling leaves and other plant matter, as well as by the underground activities of plant roots.
Short-term warming studies have documented that rising temperatures increase the rate of soil respiration. As a result, scientists have worried that global warming would accelerate the decomposition of carbon in the soil, and decrease the amount of carbon stored there. If true, this would release even more carbon dioxide into the atmosphere, where it would accelerate global warming.
New work by a team of scientists including Carnegie's Greg Asner and Christian Giardina of the U.S. Forest Service used an expansive whole-ecosystem study, the first of its kind, on tropical montane wet forests in Hawaii to sort through the many processes that control soil carbon stocks with changing temperature. Their work is published in Nature Climate Change.
The team revealed that higher temperatures increased the amount of leaf litter falling onto the soil, as well as other underground sources of carbon such as roots. Surprisingly, long-term warming had little effect on the overall storage of carbon in the tropical forest soil or the rate at which that carbon is processed into carbon dioxide.
"If these findings hold true in other tropical regions, then warmer temperatures may not necessarily cause tropical soils to release their carbon to the atmosphere at a faster rate," remarked Asner. "On the other hand, we cannot expect that the soil will soak up more carbon in places where vegetation is stimulated by warmer temperatures. Unlike tropical trees, the soil seems to be on the sidelines in the climate adaptation game."
This means the observed increase in the rate of soil respiration accompanying rising temperatures is due to carbon dioxide released by the an uptick in the amount of litter falling on the forest floor and an increase in carbon from underground sources. It is not from a decrease in the overall amount of carbon stored in the soil.
Giardina noted "While we found that carbon stored in the mineral soil was insensitive to long-term warming, the loss of unprotected carbon responded strongly to temperature. This tells us that the sensitivity of each source of soil respiration needs to be quantified, and the aggregate response examined, before an understanding of ecosystem carbon balance in a warmer world can be achieved."
This work was funded by the National Science Foundation, the College of Tropical Agriculture and Human Resources at the University of Hawaii at Manoa, the USDA Forest Service, and the Carnegie Institution for Science.
The Carnegie Airborne Observatory is made possible by the Avatar Alliance Foundation, John D. and Catherine T. MacArthur Foundation, Grantham Foundation for the Protection of the Environment, Gordon and Betty Moore Foundation, W. M. Keck Foundation, the Margaret A. Cargill Foundation, Mary Anne Nyburg Baker and G. Leonard Baker Jr., and William R. Hearst III.
The Carnegie Institution for Science is a private, nonprofit organization headquartered in Washington, DC, with six research departments throughout the U.S. Since its founding in 1902, the Carnegie Institution has been a pioneering force in basic scientific research. Carnegie scientists are leaders in plant biology, developmental biology, astronomy, materials science, global ecology, and Earth and planetary science.
Greg Asner | Eurek Alert!
Researchers find higher than expected carbon emissions from inland waterways
25.05.2016 | Washington State University
Rutgers scientists help create world's largest coral gene database
24.05.2016 | Rutgers University
A biological and energy-efficient process, developed and patented by the University of Innsbruck, converts nitrogen compounds in wastewater treatment facilities into harmless atmospheric nitrogen gas. This innovative technology is now being refined and marketed jointly with the United States’ DC Water and Sewer Authority (DC Water). The largest DEMON®-system in a wastewater treatment plant is currently being built in Washington, DC.
The DEMON®-system was developed and patented by the University of Innsbruck 11 years ago. Today this successful technology has been implemented in about 70...
Permanent magnets are very important for technologies of the future like electromobility and renewable energy, and rare earth elements (REE) are necessary for their manufacture. The Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany, has now succeeded in identifying promising approaches and materials for new permanent magnets through use of an in-house simulation process based on high-throughput screening (HTS). The team was able to improve magnetic properties this way and at the same time replaced REE with elements that are less expensive and readily available. The results were published in the online technical journal “Scientific Reports”.
The starting point for IWM researchers Wolfgang Körner, Georg Krugel, and Christian Elsässer was a neodymium-iron-nitrogen compound based on a type of...
In the Beyond EUV project, the Fraunhofer Institutes for Laser Technology ILT in Aachen and for Applied Optics and Precision Engineering IOF in Jena are developing key technologies for the manufacture of a new generation of microchips using EUV radiation at a wavelength of 6.7 nm. The resulting structures are barely thicker than single atoms, and they make it possible to produce extremely integrated circuits for such items as wearables or mind-controlled prosthetic limbs.
In 1965 Gordon Moore formulated the law that came to be named after him, which states that the complexity of integrated circuits doubles every one to two...
Characterization of high-quality material reveals important details relevant to next generation nanoelectronic devices
Quantum mechanics is the field of physics governing the behavior of things on atomic scales, where things work very differently from our everyday world.
When current comes in discrete packages: Viennese scientists unravel the quantum properties of the carbon material graphene
In 2010 the Nobel Prize in physics was awarded for the discovery of the exceptional material graphene, which consists of a single layer of carbon atoms...
24.05.2016 | Event News
20.05.2016 | Event News
19.05.2016 | Event News
27.05.2016 | Awards Funding
27.05.2016 | Life Sciences
27.05.2016 | Life Sciences