Featured Research

from universities, journals, and other organizations

Microbe community changes may reduce Amazon's ability to lock up carbon dioxide

Date:
January 7, 2014
Source:
University of Texas at Arlington
Summary:
A new paper looks for the first time at the reaction of free-living nitrogen-fixing microorganisms called diazotrophs to the conversion of rainforests to pastureland in the Amazon. Researchers found big changes to the diazotroph communities that they say may reduce the region's ability to act as a reservoir for greenhouse gas.

UT Arlington researchers focusing on the Amazon recently found that widespread conversion from rainforest to pastureland has significant effects on microorganism communities that may lead to a reduction in the region's role as a reservoir for greenhouse gas.

The Amazon rainforest is the largest terrestrial reservoir or "sink" for carbon dioxide, a gas that has been linked to climate change. Through photosynthesis, the Amazon absorbs 1.5 billion tons of carbon dioxide from the atmosphere every year in a process that requires input of nitrogen. That nitrogen, for the most part, comes from a process called nitrogen fixation -- essentially microbes pulling nitrogen form the air into the soil.

The new paper, featured in the January issue of Applied and Environmental Microbiology, looks for the first time at the reaction of free-living nitrogen-fixing microorganisms called diazotrophs to the deforestation. Jorge Rodrigues, an assistant professor of biology at The University of Texas at Arlington, organized the work. Babur S. Mirza, formerly a postdoctoral fellow in the Rodrigues lab, is the paper's lead author.

"This study shows that although the diversity of diazotrophic microorganisms remains the same with the conversion from forest to pasture, the types of species found are different," said Rodrigues. "Our next step is to measure how the rates of biological nitrogen fixation are influenced by community changes. Because the carbon and nitrogen cycles are so strongly linked, our previous results indicated that changes in carbon dioxide sequestration will occur"

Rodrigues' team gathered samples of soil from the Fazenda Nova Vida site in Rondonia, Brazil, one of three states in the country that accounted for more than 85 percent of deforestation from 1996 to 2005. They analyzed soil from a primary forest, a pasture established in 2004 and a secondary forest that resulted from the abandonment of a pasture in 1999.

The team used DNA analysis, specifically the nifH gene that is characteristic of diazotrophs, to measure the communities in the samples.

Rodrigues said researchers were surprised to find a ten-fold increase in the number of diazotrophic microorganisms in the pasture established in 2004, when compared to the primary forests. They theorize the pasture ecosystems rely on the diazotrophs more for nitrogen because of the continuous grazing from cattle, requiring constant regrowth of grasses.

"We observed a complete shift in the diazotrophic microbial community composition in response to the Amazon rain forest conversion to a pasture," Mirza said. "These differences an be attributed to the shift in the above ground plant community because we did see partial recovery of diazotroph community composition in the secondary forest, which have more plant species as compared to pasture."

Mirza said researchers are continuing their work with more more sophisticated sequencing technologies and in-depth sampling.

Despite worries about the effect these changes to the microbial communities may have on the carbon cycle, Rodrigues said there are some encouraging results. After pastures were abandoned and a secondary forest grew, partial restoration of the original diazotrophic communities was achieved, researchers said.

Growth of secondary forest is ongoing for about 50 percent of the abandoned pastures in the Amazon, but more needs to be done to encourage secondary forests and limit deforestation in the first place, Rodrigues said.

"There is still time to recover if we act now," he said.


Story Source:

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


Journal Reference:

  1. B. S. Mirza, C. Potisap, K. Nusslein, B. J. M. Bohannan, J. L. M. Rodrigues. Response of Free-Living Nitrogen-Fixing Microorganisms to Land Use Change in the Amazon Rainforest. Applied and Environmental Microbiology, 2013; 80 (1): 281 DOI: 10.1128/AEM.02362-13

Cite This Page:

University of Texas at Arlington. "Microbe community changes may reduce Amazon's ability to lock up carbon dioxide." ScienceDaily. ScienceDaily, 7 January 2014. <www.sciencedaily.com/releases/2014/01/140107170915.htm>.
University of Texas at Arlington. (2014, January 7). Microbe community changes may reduce Amazon's ability to lock up carbon dioxide. ScienceDaily. Retrieved September 22, 2014 from www.sciencedaily.com/releases/2014/01/140107170915.htm
University of Texas at Arlington. "Microbe community changes may reduce Amazon's ability to lock up carbon dioxide." ScienceDaily. www.sciencedaily.com/releases/2014/01/140107170915.htm (accessed September 22, 2014).

Share This



More Earth & Climate News

Monday, September 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Will Climate Rallies Spur Change?

Will Climate Rallies Spur Change?

Newsy (Sep. 21, 2014) Organizers of the People's Climate March and other rallies taking place in 166 countries hope to move U.N. officials to action ahead of their summit. Video provided by Newsy
Powered by NewsLook.com
Thousands March in NYC Over Climate Change

Thousands March in NYC Over Climate Change

AP (Sep. 21, 2014) Accompanied by drumbeats, wearing costumes and carrying signs, thousands of demonstrators filled the streets of Manhattan and other cities around the world on Sunday to urge policy makers to take action on climate change. (Sept. 21) Video provided by AP
Powered by NewsLook.com
Climate Change Rally Held in India Ahead of UN Summit

Climate Change Rally Held in India Ahead of UN Summit

AFP (Sep. 20, 2014) Some 125 world leaders are expected to commit to action on climate change at a UN summit Tuesday called to inject momentum in struggling efforts to tackle global warming. Duration: 00:41 Video provided by AFP
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

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