Nav: Home

Soil organic matter susceptible to climate change

March 31, 2015

Soil organic matter, long thought to be a semi-permanent storehouse for ancient carbon, may be much more vulnerable to climate change than previously thought.

Plants direct between 40 percent and 60 percent of photosynthetically fixed carbon to their roots and much of this carbon is secreted and then taken up by root-associated soil microorganisms. Elevated carbon dioxide (CO2) concentrations in the atmosphere are projected to increase the quantity and alter the composition of root secretions released into the soil.

In new research in the March 30 edition of the journal, Nature Climate Change, Lawrence Livermore scientists and collaborators found that the common root secretion, oxalic acid, can promote soil carbon loss by an unconventional mechanism -- freeing organic compounds from protective associations with minerals.

Root secretion-induced soil carbon loss is commonly attributed to "priming" -- a short-term increase in microbial mineralization of native soil carbon as a result of fresh carbon inputs to the soil.

Previous studies have suggested that climate change enhances root secretions of organic compounds into soils. Recent experimental studies show that increased root secretion inputs may cause a net loss of soil carbon This stimulation of microbial carbon mineralization, or "priming," is commonly explained by the notion of 'cometabolism', i.e. that root secretions provide a readily bioavailable supply of energy for the decomposition of native soil carbon.

"Our Lawrence Scholar Marco Keiluweit showed that an alternate mechanism can cause carbon loss of equal or greater magnitude," said Jennifer Pett-Ridge, an LLNL scientist and one of the co-authors on the paper. "By enhancing microbial access to previously mineral-protected compounds, some root secretions promote an indirect mechanism of accelerated carbon loss, more than simply increasing the supply of energetically more favorable substrates.

"Our results provide new insights into the coupled biotic-abiotic mechanisms underlying the 'priming' phenomenon and challenge the assumption that mineral-associated carbon is protected from microbial cycling over millennial timescales," she said.

"Our study revealed a climate dependent `priming' mechanism where plant secretions counteract the strong protective mineral-organic associations and facilitate the loss of carbon from the soil system," Pett-Ridge said. "If root secretion rates respond to climate change as predicted, elevated CO2 concentrations may not only stimulate secretion, they also may alter the composition of those secreted compounds released into soil, and increase metal and organic matter mobilization in the rooting zone."
-end-
The work was done using two unique technological capabilities, the NanoSIMS at Livermore and the synchrotron spectroscopy at Lawrence Berkeley National Laboratory.

Other Livermore scientists include Peter Weber and Jeremy Bougoure (now at University of Western Australia). Collaborating institutions include Oregon State University and Lawrence Berkeley National Laboratory. The work was supported by funding from the LLNL's Laboratory Directed Research and Development (LDRD) program and the Department of Energy (OBER) Genomic Science program."

Founded in 1952, Lawrence Livermore National Laboratory provides solutions to our nation's most important national security challenges through innovative science, engineering and technology. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.

DOE/Lawrence Livermore National Laboratory

Related Climate Change Articles:

Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.
Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.
Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.
Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.
A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.
Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).
Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.
Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.
Could climate change cause infertility?
A number of plant and animal species could find it increasingly difficult to reproduce if climate change worsens and global temperatures become more extreme -- a stark warning highlighted by new scientific research.
Predicting climate change
Thomas Crowther, ETH Zurich identifies long-disappeared forests available for restoration across the world.
More Climate Change News and Climate Change Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.