Featured Research

from universities, journals, and other organizations

Toxic methylmercury-producing microbes more widespread than realized

Date:
September 12, 2013
Source:
Oak Ridge National Laboratory
Summary:
Microbes that live in rice paddies, northern peat bogs and other previously unexpected environments are among the bacteria that can generate highly toxic methylmercury, researchers have learned.

Newly discovered archaeal (green) and bacterial (blue) organisms that are free-living or within another organism on the tree of life, and their larger environments.
Credit: Oak Ridge National Library

Microbes that live in rice paddies, northern peat bogs and other previously unexpected environments are among the bacteria that can generate highly toxic methylmercury, researchers at Oak Ridge National Laboratory and the Smithsonian Environmental Research Center have learned.

Related Articles


This finding, published in Environmental Science and Technology, explains why deadly methylated mercury is produced in areas where the neurotoxin's presence has puzzled researchers for decades. Methylmercury -- the most dangerous form of mercury -- damages the brain and immune system and is especially harmful to developing embryos. Certain bacteria transform inorganic mercury into toxic methylmercury.

The discovery also validates the recent finding that two genes are essential for the methylation of mercury. Previously, only a narrow range of microbes were recognized as mercury methylators, said co-author Dwayne Elias of the Department of Energy laboratory's Biosciences Division.

"We showed for the first time that many different types of bacteria are able to produce this potent neurotoxin," Elias said. "The newly identified microbes include methane-producing organisms that live in rice paddies, anaerobic wastewater treatment plants, northern peat lands and possibly within our bodies."

Elias and colleagues are testing a bacterium from the human intestine that they predict will also methylate mercury. Other bacteria able to transform inorganic into methylmercury include those used in biological dechlorination and metal treatment systems. All of these organisms are anaerobic, which means they grow in habitats without oxygen, including aquatic sediments and wetland soils.

By identifying these organisms, the researchers may have explained why methylmercury is accumulating in unexpected places. The discovery may also help clarify how methylmercury is produced in the open ocean, according to co-author Cindy Gilmour of the Smithsonian Environmental Research Center. Gilmour noted that the newly identified fermentative bacteria may be common in the low oxygen zones of the ocean where methylmercury production occurs. Ocean fish are the primary source of methylmercury in human diets worldwide.

Gilmour and Elias believe this work will have far-reaching implications for understanding the global mercury cycle. Scientists can now use the mercury-methylating organisms and their genes as global biomarkers and develop detection techniques to assess and eventually predict the extent of methylmercury production in a given environment.

"Based on the substantially expanded diversity of organisms and environments for methylation, a number of important habitats deserve further attention," Gilmour said. "We now have a way to identify and track the abundance of mercury-methylating organisms within these environments, and we hope that the information can be used to devise strategies to minimize methylmercury production."

Mercury is a global pollutant, released to the atmosphere through coal burning and other industrial uses, and through natural processes. Most of the harm comes from methylmercury bioaccumulation, which is the buildup of the element in tissue that occurs when moving up the food chain.


Story Source:

The above story is based on materials provided by Oak Ridge National Laboratory. Note: Materials may be edited for content and length.


Journal Reference:

  1. Cynthia C. Gilmour, Mircea Podar, Allyson L Bullock, Andrew Mitchell Graham, Steven Brown, Anil C Somenahally, Alexander Johs, Richard Hurt, Kathryn L Bailey, Dwayne Elias. Mercury methylation by novel microorganisms from new environments. Environmental Science & Technology, 2013; 130911100953003 DOI: 10.1021/es403075t

Cite This Page:

Oak Ridge National Laboratory. "Toxic methylmercury-producing microbes more widespread than realized." ScienceDaily. ScienceDaily, 12 September 2013. <www.sciencedaily.com/releases/2013/09/130912155529.htm>.
Oak Ridge National Laboratory. (2013, September 12). Toxic methylmercury-producing microbes more widespread than realized. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2013/09/130912155529.htm
Oak Ridge National Laboratory. "Toxic methylmercury-producing microbes more widespread than realized." ScienceDaily. www.sciencedaily.com/releases/2013/09/130912155529.htm (accessed October 24, 2014).

Share This



More Earth & Climate News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

Reuters - Light News Video Online (Oct. 22, 2014) The pair of rare white northern rhinos bring hope for their species as only six remain in the world. Elly Park reports. Video provided by Reuters
Powered by NewsLook.com
Trick-or-Treating Banned Because of Polar Bears

Trick-or-Treating Banned Because of Polar Bears

Buzz60 (Oct. 21, 2014) Mother Nature is pulling a trick on the kids of Arviat, Canada. As Mara Montalbano (@maramontalbano) tells us, the effects of global warming caused the town to ban trick-or-treating this Halloween. Video provided by Buzz60
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 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:

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