Microbes In Marine Sediments React To Temperature Changes

FLORA AND FAUNA

Athens GA (SPX) Nov 16, 2005
Marine scientists from the University of Georgia have shown for the first time that temperature affects the biological activity of microbes that degrade organic carbon in marine sediments, and could therefore cause shifts in the balance of organic carbon that is recycled into the atmosphere or buried in sediments that serve as reservoirs for the substance.

Relatively little has been known until now about how temperature affects this microbial process, which is responsible for the initial breakdown of complex organic matter in sediments, said oceanographer Samantha Joye of the University of Georgia and lead scientist on the study.

"What we report was completely unexpected. Temperature short-circuits organic matter recycling," she said.

Joye and coworker, Nathaniel Weston, are publishing their results the week of Nov.14 in the Proceedings of the National Academy of Sciences.

"These surprising results show that temperature strongly affects organic matter breakdown and needs to be taken into account in understanding the role of sediments in the global carbon cycle," said Paul Kemp, program director in the National Science Foundation (NSF)'s Biological Oceanography Program, which supported the research along with NSF's Long-Term Ecological Research (LTER) Program.

The research was conducted at the Georgia Coastal Ecosystems LTER site located on the central Ga. coast and encompassing the estuaries, sounds and marshes surrounding Sapelo Island, Ga. There a buffer of barrier islands protect vast expanses of tidal salt marshes.

Scientists have long known that buried organic carbon in marine sediments plays a crucial role in many terrestrial and atmospheric processes. The number of microorganisms that feast upon this carbon is vast.

"The microbes responsible for organic matter degradation in sediments are often ignored," said Weston. "We were interested in opening the microbial 'black box' in sediments and clarifying the temperature controls on different microbial groups."

Weston and Joye studied sediment cores from Umbrella Creek near the mouth of the Satilla River on the Ga. coast. By sampling sediments at different times of the year, they found that temperature affected the processes that led to the breakdown of organic carbon. Microbes at work in sediments have different optimal temperature ranges, and thus operate at different rates, depending on temperature.

"Microbial processes involved in organic carbon breakdown are extremely sensitive to even small changes in temperature," said Joye. "These results suggest that global climate change may influence the efficiency of organic carbon recycling," impacting coastal ecosystems.

It's as yet unknown, said Joye, whether the temperature-driven changes documented for marine sediments in Ga., located in a temperate climate region, will apply to other geographic zones, such as tropical environments.

The research was also supported by the Georgia Sea Grant Program.

FLORA AND FAUNA

US To End Federal Protection For Yellowstone Grizzly Bears

Washington (AFP) Nov 15, 2005
The US government said Tuesday that grizzly bears in the Yellowstone National Park and its surroundings were no longer under threat and would be taken off a list of protected species.

Thanks for being here; We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor $5 Billed Once credit card or paypal		SpaceDaily Monthly Supporter $5 Billed Monthly paypal only

The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.