Featured Research

from universities, journals, and other organizations

Can clouds help mitigate global warming? Missing links found in biology of cloud formation over oceans

Date:
May 12, 2011
Source:
University of Georgia
Summary:
A new study brings the possibility of using the sulfur cycle to mitigate global warming closer with the identification of the steps in the biochemical pathway that controls how bacteria release the sulfur compound methanethiol, or MeSH, into the microbial food web in the oceans and the genes responsible for that process.

A simplified graphic shows the process by which bacterioplankton send sulfur found in decaying algae into the food web or into the atmosphere, where it leads to water droplet formation -- the basis of clouds that cool the Earth.
Credit: Chris Reisch, University of Georgia

Scientists have known for two decades that sulfur compounds that are produced by bacterioplankton as they consume decaying algae in the ocean cycle through two paths. In one, a sulfur compound dimethylsulfide, or DMS, goes into the atmosphere, where it leads to water droplet formation -- the basis of clouds that cool Earth. In the other, a sulfur compound goes into the ocean's food web, where it is eaten and returned to seawater.

Related Articles


What they haven't known is how sulfur is routed one way or the other or why.

They also have wondered what if -- in a time of growing concern about global warming -- it was possible to divert the sulfur compound that goes into the oceans into the atmosphere, helping to mitigate global warming?

A study by researchers at the University of Georgia just published in Nature brings the possibility of using the sulfur cycle to mitigate global warming closer with the identification of the steps in the biochemical pathway that controls how bacteria release the sulfur compound methanethiol, or MeSH, into the microbial food web in the oceans and the genes responsible for that process.

"With our increased understanding of the sulfur cycle in the ocean," said study co-author William (Barny) Whitman, "we are now better able to evaluate the impacts of climate change on the process and the potential for its manipulation, which has been proposed as a way to mitigate global warming.

"It's wonderful to have this much understanding of a major biogeochemical process," noted Whitman, distinguished research professor and head of the department of microbiology in the Franklin College of Arts and Sciences.

In addition to elucidating the steps in the pathway and identifying the responsible genes, the team of UGA microbiologists, marine scientists and chemists discovered that the pathway is found widely, not only among bacterioplankton in the ocean but also in non-marine environments.

"The big mystery about bacteria is what they are doing in nature," Whitman said. "The organisms metabolize compounds for their own needs. We need to understand what they are getting out of it to understand what it means for the ocean, and now it will be possible to look at the environmental importance of this process and how it's regulated." That will help to answer the "why" of the two sulfur fates.

Co-authors of the Nature paper were UGA graduate students Chris Reisch and Vanessa Varaljay, department of microbiology; graduate student Melissa Stoudemayer and Jon Amster, professor and head, department of chemistry; and distinguished research professor Mary Ann Moran, department of marine sciences -- all in the Franklin College of Arts and Sciences.

The collaborators in this study built on a line of research begun at UGA over a decade ago. Moran's early research showed that an abundant group of bacteria known as marine roseobacters play a role in moving dimethylsulfonioproprionate (DMSP), the chemical made by marine algae and released into the water upon their death, into the atmosphere as the compound dimethylsulfide (DMS).

In 2006, Moran's research group discovered in marine bacteria the first step in the process of turning DMSP into MeSH, instead of sending sulfur into the atmosphere. And in 2008, Moran's doctoral student Erinn Howard, in collaboration with Whitman's lab, discovered the gene that allows marine roseobacters to keep sulfur in the ocean.

With funding from the National Science Foundation and the Gordon and Betty Moore Foundation, the UGA researchers have now identified the rest of the pathway, including identifying two previously unknown but related chemical compounds that serve as intermediates between MMPA, the first product of degraded DMSP, and MeSH, the final product.

The collaboration with UGA chemists using high-resolution mass spectrometry made it possible for the researchers to identify the compounds. A major surprise was the presence of Coenzyme A (CoA), a large molecule important in metabolism, in the intermediate compounds.

"We weren't really expecting CoA to be involved," said Reisch, who was part of the UGA group that five years ago identified the first step in the pathway that produces MeSH. "We thought they would be smaller fatty acids."

With the discovery of the intermediates, it was possible to find the enzymes that catalyzed the reaction and then the genes. And once the genes were discovered, the researchers were able to analyze databases of marine bacteria to determine which bacteria possess the genes capable of carrying out the MeSH process.

The group discovered that the MeSH pathway is widespread among bacterioplankton in the ocean. "The genes may be in up to 61 percent of surface ocean bacterioplankton," said Reisch, "while the DMS pathway is present in less than 5 percent of cells." However, he said, "There could be a lot more that we don't yet know about. Some bacteria, including the model bacteria used in the study, have both pathways."

But the researchers also found the genes for the MeSH pathway in bacteria from a variety of non-marine habitats, including bacteria commonly found in soils, plants, extreme environments and humans. They note in their Nature paper that the presence of the newly discovered pathway in diverse bacteria further emphasizes its importance.


Story Source:

The above story is based on materials provided by University of Georgia. The original article was written by Terry Marie Hastings. Note: Materials may be edited for content and length.


Journal Reference:

  1. Chris R. Reisch, Melissa J. Stoudemayer, Vanessa A. Varaljay, I. Jonathan Amster, Mary Ann Moran, William B. Whitman. Novel pathway for assimilation of dimethylsulphoniopropionate widespread in marine bacteria. Nature, 2011; 473 (7346): 208 DOI: 10.1038/nature10078

Cite This Page:

University of Georgia. "Can clouds help mitigate global warming? Missing links found in biology of cloud formation over oceans." ScienceDaily. ScienceDaily, 12 May 2011. <www.sciencedaily.com/releases/2011/05/110511134209.htm>.
University of Georgia. (2011, May 12). Can clouds help mitigate global warming? Missing links found in biology of cloud formation over oceans. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2011/05/110511134209.htm
University of Georgia. "Can clouds help mitigate global warming? Missing links found in biology of cloud formation over oceans." ScienceDaily. www.sciencedaily.com/releases/2011/05/110511134209.htm (accessed October 25, 2014).

Share This



More Plants & Animals News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
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
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
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