Featured Research

from universities, journals, and other organizations

Microbe Diet Key To Carbon Dioxide Release

Date:
August 5, 2008
Source:
Duke University
Summary:
As microbes in the soil break down fallen plant matter, a diet "balanced" in nutrients appears to help control soil fertility and the normal release of the greenhouse gas carbon dioxide into the atmosphere.

As microbes in the soil break down fallen plant matter, a diet “balanced” in nutrients appears to help control soil fertility and the normal release of the greenhouse gas carbon dioxide into the atmosphere.
Credit: Composite photo by Stefano Manzoni

As microbes in the soil break down fallen plant matter, a diet "balanced" in nutrients appears to help control soil fertility and the normal release of the greenhouse gas carbon dioxide into the atmosphere.

Related Articles


When plants drop their leaves, stems and twigs, this organic matter slowly becomes part of the soil as a result of decomposition, which is facilitated by bacteria and other microbes. This process adds plant nutrients to the soil and releases carbon dioxide into the atmosphere.

Duke University scientists found the proportion of nitrogen to carbon in this organic matter determines how much nitrogen becomes available to plants in the soil and how much carbon dioxide is released into the atmosphere. Their study also yielded a universal mathematical formula that can predict the decomposition process anywhere in the world.

The results of the Duke analysis were published Aug. 1 in the journal Science.

"For the first time, we have been able to demonstrate that the pattern of carbon dioxide release into the atmosphere through decomposition is governed by the same properties everywhere, from the Arctic Circle to tropical rain forests," said first author Stefano Manzoni, a Ph.D. candidate in civil and environmental engineering who works in the laboratory of senior scientist Amilcare Porporato, associate professor of civil engineering in Duke's Pratt School of Engineering. "This provides a mathematical way of describing a critical natural process."

During decomposition, microbes digest fallen organic matter from plants and slowly break it down. Two of the important byproducts of this process are mineral nitrogen and carbon dioxide. Nitrogen is an essential nutrient for both plants and microbes, and once it becomes mineralized, it becomes available for plants to use.

Carbon -- the most abundant element in plants and organic matter -- is released into the atmosphere in the form of carbon dioxide, one of many of the so-called greenhouse gases implicated in global warning. This carbon dioxide release is known as respiration.

"One of the key findings of this study is that microbes can adapt and do fairly well in a nutrient-poor environment," Porporato said. "When their diet is lacking in nitrogen, microbes tend to react by releasing more carbon dioxide into the air and taking in less mineral nitrogen from the soil. So plants can get the much-needed mineralized nitrogen earlier in the decomposition process from the fallen organic matter."

However, he pointed out, the earlier availability of mineral nitrogen for plant use comes at a risk: nitrogen in this form in the soil becomes more vulnerable to rain, which can wash it away or leach it deeper into the soil. This would be especially true if the rainfall events are particularly heavy, as has been predicted in some climate-change models.

Maintaining enough soil nitrogen is important in both native ecosystems and in farms and orchards, the scientists said.

"Nitrogen is the element that most limits plant growth around the world," said co-author Rob Jackson, Duke professor of biology and environmental sciences. "Our work should help predict how much nitrogen becomes available when organic matter is added to the soil, either naturally or through added mulches and manures."

For the analysis, Manzoni assembled a database of more than 2,800 samples of decomposing plant matter from locations around the world in a wide spectrum of climates. As he studied decomposition across these sites, he found similar patterns of nitrogen release and respiration no matter what the climate was like.

"A diet rich in carbon causes microbes to release more carbon into the atmosphere in the form of carbon dioxide as they strive to maintain the healthy balance between nitrogen and carbon in their diet," Manzoni said. "For this reason, if more carbon is added to the soil in the form of plant residues, the microbes would then just pump out more carbon in response."

The research team plans to use the same approach to better understand the roles of other nutrients in the decomposition cycle.

The research was funded by the U.S. Department of Energy and the National Science Foundation. John Trofymow of the Canadian Forest Service was also a member of the team. Much of the data used in the current analysis came from the Long-Term Intersite Decomposition Experiment (LIDET), a partnership of the U.S Forest Service, Oregon State University and the U.S. Department of Forest Science, as well as the Canadian Intersite Decomposition Experiment (CIDET).


Story Source:

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


Cite This Page:

Duke University. "Microbe Diet Key To Carbon Dioxide Release." ScienceDaily. ScienceDaily, 5 August 2008. <www.sciencedaily.com/releases/2008/07/080731173125.htm>.
Duke University. (2008, August 5). Microbe Diet Key To Carbon Dioxide Release. ScienceDaily. Retrieved January 29, 2015 from www.sciencedaily.com/releases/2008/07/080731173125.htm
Duke University. "Microbe Diet Key To Carbon Dioxide Release." ScienceDaily. www.sciencedaily.com/releases/2008/07/080731173125.htm (accessed January 29, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Thursday, January 29, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Dogs Bring on So Many Different Emotions in Their Human Best Friends

Dogs Bring on So Many Different Emotions in Their Human Best Friends

RightThisMinute (Jan. 28, 2015) From new-puppy happy tears to helpful-grocery-carrying-dog laughter, our four-legged best friends can make us feel the entire spectrum of emotions. Video provided by RightThisMinute
Powered by NewsLook.com
Scientists Say Earliest Snakes Lived Alongside The Dinosaurs

Scientists Say Earliest Snakes Lived Alongside The Dinosaurs

Newsy (Jan. 28, 2015) Wrongly categorized as lizard fossils, snake fossils now show the reptile could have developed earlier than we thought — 70 million years earlier. Video provided by Newsy
Powered by NewsLook.com
Malnutrition on the Rise as Violence Flares in C. Africa

Malnutrition on the Rise as Violence Flares in C. Africa

AFP (Jan. 28, 2015) Violence can flare up at any moment in Bambari with only a bridge separating Muslims and Christians. Malnutrition is on the rise and lack of water means simple cooking fires threaten to destroy makeshift camps where people are living. Duration: 00:40 Video provided by AFP
Powered by NewsLook.com
Poultry Culled in Taiwan to Thwart Bird Flu

Poultry Culled in Taiwan to Thwart Bird Flu

Reuters - News Video Online (Jan. 28, 2015) Taiwan culls over a million poultry in efforts to halt various strains of avian flu. Julie Noce reports. Video provided by Reuters
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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