The Earth’s soils store four times more carbon than the atmosphere and small changes in soil carbon storage can have a big effect on atmospheric greenhouse gas concentrations. A new paper in the journal Nature Climate Change concludes that climate warming does not accelerate soil organic carbon decomposition or affect soil carbon storage, despite increases in ecosystem productivity.
The research, led by U.S. Forest Service Research Ecologist Dr. Christian Giardina, with the agency’s Institute of Pacific Islands Forestry, Pacific Southwest Research Station, with co-authors Drs. Creighton Litton and Susan Crow (University of Hawai`i at Manoa), and Dr. Greg Asner (Carnegie Institution for Science), shows that soil carbon storage was constant across a highly constrained 5 degrees Celsius gradient of mean annual temperature in tropical montane wet forest in Hawai`i.
The scientists also showed an increase in productivity across the gradient, both above and belowground, and an increase in the decomposition rate of fresh litter and a decline in coarse woody debris with warming. From these results, they concluded that long-term warming in tropical montane forests will accelerate carbon cycling, but is unlikely to cause net losses of soil carbon.
“Given our findings, we expect that warming alone, that is in the absence of other changes such as drying or increased fire, will not accelerate the loss of carbon from mineral soils,” says Giardina. “This means that tropical soils will not become a net source of CO2 to the atmosphere.”
The effects of warming on soil carbon storage are poorly quantified because it is difficult to assess how temperature change impacts processes below the soil surface. However, the temperature gradient used in this study provides an ideal study system for measuring ecosystem responses to warming over long periods of time. The scientists were careful to find a gradient of temperature change where potentially confounding factors were held constant, including vegetation composition, disturbance history, geology, and soil type and moisture. This allowed them to isolate the effects of changing temperature on ecosystem carbon storage and flux.
The scientists propose that where ecosystem carbon is unprotected, such as at the surface in plant debris, its decomposition and storage will respond strongly to warming. However, when carbon is protected in the soil, decomposer organisms have reduced access to that carbon and so decomposition or storage show little temperature sensitivity. And while climate warming will continue with the addition of greenhouse gases into the atmosphere due to human activities (fossil fuel combustion, land-use clearing), previous assumptions about a positive soil carbon cycling feedback to future warming may be incorrect.
While soil carbon storage and turnover was insensitive to warming, the decomposition of coarse wood and plant growth did increase, which means that the capacity of tropical ecosystems to retain carbon will depend on the balance of changes within each ecosystem.
To read the paper: http://www.treesearch.fs.fed.us/pubs/46423
Headquartered in Albany, Calif., the Pacific Southwest Research Station develops and communicates science needed to sustain forest ecosystems and other benefits to society. It has research facilities in California, Hawaii and the U.S.–affiliated Pacific Islands. For more information, visit www.fs.fed.us/psw/.
Sherri Eng | Eurek Alert!
New study shows producers where and how to grow cellulosic biofuel crops
17.01.2018 | University of Illinois College of Agricultural, Consumer and Environmental Sciences
Robotic weeders: to a farm near you?
10.01.2018 | American Society of Agronomy
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
17.01.2018 | Ecology, The Environment and Conservation
17.01.2018 | Physics and Astronomy
17.01.2018 | Awards Funding