Featured Research

from universities, journals, and other organizations

Increased Atmospheric Carbon Dioxide Stimulates Soils To Release, Not Store, CO2

Date:
March 13, 2007
Source:
Smithsonian Institution
Summary:
Researchers at the Smithsonian Environmental Research Center report that doubling the atmospheric greenhouse gas carbon dioxide (CO2) in a scrub oak ecosystem caused a reduction in carbon storage in the soil. This response suggests a limited capacity of Earth's ecosystems to stabilize atmospheric CO2 and slow global warming. These findings add a new perspective and a measure of caution suggesting that elevated CO2, by altering microbial communities, may turn a potential carbon sink into a carbon source.

Researchers at the Smithsonian Environmental Research Center report the results of a six-year experiment in which doubling the atmospheric greenhouse gas carbon dioxide (CO2) in a scrub oak ecosystem caused a reduction in carbon storage in the soil.

The scientists said this response suggests a limited capacity of Earth's ecosystems to stabilize atmospheric CO2 and slow global warming. These findings add a new perspective and a measure of caution suggesting that elevated CO2, by altering microbial communities, may turn a potential carbon sink into a carbon source.

Previous studies have shown that plants will respond to higher CO2 by increasing growth and taking up much of the excess carbon. This has led some to speculate that plants may be able to mitigate increases in atmospheric CO2 and that soils, which represent the largest and most stable terrestrial carbon pool, also may serve as a sink for excess carbon.

During the course of their study, Smithsonian scientists saw a consistent loss in soil carbon under high CO2 conditions. The CO2 loss from soils offset about 52 percent of the additional carbon that had accumulated in the plants above ground and in the roots.

"We were surprised to find that these soils were losing soil carbon despite the fact that there was more plant growth," said Patrick Megonigal, a microbial ecologist at SERC and one of the study's authors. "We thought that higher plant growth at elevated CO2 would either add more carbon to soils, or at least leave it the same. We now need to consider a third possibility--the carbon already in soils will end up back in the atmosphere as a greenhouse gas."

The study will be published this week in Proceedings of the National Academy of Sciences.

Working at a long-term Smithsonian experimental CO2 site in a Florida scrub oak ecosystem, the researchers compared core samples from test plots that had been exposed to six years of elevated CO2 and core samples from plots exposed to ambient CO2. They also performed laboratory experiments on soils from both elevated and ambient plots to understand microbial composition and activity within each type of soil.

Their study reveals that added CO2 has a so-called "priming effect," stimulating certain microbes and increasing decomposition. Soils exposed to the elevated CO2 had higher relative abundances of fungi and higher activities of a soil carbon-degrading enzyme. As the fungi and enzymes decompose the organic matter in the soil, they free up stored carbon and release it through respiration as CO2. With the priming effect of added CO2, more soil decomposition results in higher respiration rates, an overall loss of carbon and an increase in the release of CO2 from the soil.

Study authors are: Karen Carney and Bruce Huntgate, SERC post-doctoral fellows at the time of the study, who now work at the U.S. Agency for International Development and Northern Arizona University, respectively; Bert Drake, SERC plant physiologist; and Patrick Megonigal, SERC microbial ecologist.

The Smithsonian Environmental Research Center is the leading national research center for understanding environmental issues in the coastal zone. The world's coastal zones are home to more than 70 percent of the global population and subject to intensive activity. Through interdisciplinary, experimental research, SERC scientists are working to understand how ecosystems interact and are linked in this critical zone where the land meets the sea, and how physical and chemical processes sustain life on Earth.


Story Source:

The above story is based on materials provided by Smithsonian Institution. Note: Materials may be edited for content and length.


Cite This Page:

Smithsonian Institution. "Increased Atmospheric Carbon Dioxide Stimulates Soils To Release, Not Store, CO2." ScienceDaily. ScienceDaily, 13 March 2007. <www.sciencedaily.com/releases/2007/03/070312231814.htm>.
Smithsonian Institution. (2007, March 13). Increased Atmospheric Carbon Dioxide Stimulates Soils To Release, Not Store, CO2. ScienceDaily. Retrieved September 21, 2014 from www.sciencedaily.com/releases/2007/03/070312231814.htm
Smithsonian Institution. "Increased Atmospheric Carbon Dioxide Stimulates Soils To Release, Not Store, CO2." ScienceDaily. www.sciencedaily.com/releases/2007/03/070312231814.htm (accessed September 21, 2014).

Share This



More Matter & Energy News

Sunday, September 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

What This MIT Sensor Could Mean For The Future Of Robotics

What This MIT Sensor Could Mean For The Future Of Robotics

Newsy (Sep. 20, 2014) MIT researchers developed a light-based sensor that gives robots 100 times the sensitivity of a human finger, allowing for "unprecedented dexterity." Video provided by Newsy
Powered by NewsLook.com
MIT BioSuit A New Take On Traditional Spacesuits

MIT BioSuit A New Take On Traditional Spacesuits

Newsy (Sep. 19, 2014) The MIT BioSuit could be an alternative to big, bulky traditional spacesuits, but the concept needs some work. Video provided by Newsy
Powered by NewsLook.com
New Music With Recycled Instruments at Colombia Fest

New Music With Recycled Instruments at Colombia Fest

AFP (Sep. 19, 2014) Jars, bottles, caps and even a pizza box, recovered from the trash, were the elements used by four musical groups at the "RSFEST2014 Sonorities Recycling Festival", in Colombian city of Cali. Duration: 00:49 Video provided by AFP
Powered by NewsLook.com
Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins