Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Undersea microbes active but living on the slow side

21.02.2006


University Park, Pa. Ð Deeply buried ocean sediments may house populations of tiny organisms that have extremely low maintenance energy needs and population turnover rates of anywhere from 200 to 2,000 years, according to an international team of researchers.

"The microbial ecosystem in deeply buried marine sediments may comprise a tenth of Earth’s living biomass, but little is known about the organisms, their physiologies, and their influence on surface environments," says Jennifer F. Biddle, graduate student in biochemistry, microbiology and molecular biology and member of the NASA- sponsored Penn State Astrobiology Research Center.

The populations of interest are two groups of Archaea Ð tiny bacteria-like organisms that are often found in extreme environments such as deep-sea hot vents, inside cows or termites or in deep sediments. The samples were gathered during the National Science Foundation-sponsored Ocean Drilling Program Leg 201 off the coast of Peru.



"The samples showed strikingly elevated concentrations of cells in deeply buried sulfate-methane transition zones," says Dr. Christopher H. House, assistant professor of geosciences, Penn State. "Sulfate methane transition zones are areas where both methane and sulfate diffuse and both compounds are used by local denizens."

The researchers looked for 16S rRNA in the sediment samples and found the transition zones dominated by two groups Ð Marine Benthic Group B and Miscellaneous Crenarchaeotal Group. rRNA is found in a cell’s ribosome and is part of the protein manufacturing mechanism of a cell. The presence of a specific sequence of 16S rRNA distinguishes the types of Archaea and the analysis also identifies Archaea that are active, excluding inactive cells and fossils.

"Other researchers have found DNA analysis of sediments from some sites to indicate that the majority of organisms were Bacteria and not Archaea," says House. "We used methods that identify only active cells and found Archaea."

Another method of identifying the active populations Ð both in size and type Ð looked at intact polar lipids, an indication of live rather than fossil cells.

"These tests and others indicate that there is a sizeable and active archaeal community," says House.

Besides simply knowing that populations of Archaea exist in the deep sediment layers at the sulfate-methane transition zones, the researchers looked at the energy sources for these microbes. Many organisms living in environments with methane use the methane for energy and use the methane’s carbon to grow, repair and reproduce. Looking at the carbon isotopes the researchers found that few if any of these Archaea used methane as a carbon source. They also found that conversion of carbon dioxide to methane was not fueling these Archaea.

"Because the carbon isotopes from the Archaea match the total organic carbon found in the sediment in general, it suggests that the bulk archaeal community uses organic compounds derived from fossil organic matter," says House.

The researchers suggest in this weekÕs issue of the Proceedings of the National Academy of Sciences online, that degradation of organic matter in the sediment, especially the formation of small molecules like acetate and formate, are the likely sources of carbon.

"Real maintenance energies in subsurface environments must be much lower than what has been experimentally determined in laboratory cultures," says Biddle. "If conventional maintenance energies are used, only about 2 percent maximum of the population could survive. However, cellular maintenance energies are expected to be significantly lower when cells divide at extremely low rates."

In fact, the researchers estimate that these Archaea may completely turn over population as frequently as every 70 years, or as infrequently as 2,150 years. They also suggest that the sulfate-methane transition zone is a much better environment than other areas in the sediment and that turnover rates are even lower away from the transition zone.

This is because the Archaea in the transition zone, while not using the carbon from methane oxidation, are still getting some energy from breaking down the methane molecules, energy that is not available in other portions of the sediment.

"These Archaea subsist on the sedimentary organic carbon available and the energy from breaking down methane until they accumulate enough resources to divide," says House. "Surprisingly they require much less energy to maintain and take much longer than expected until they can divide."

This international research team was lead by House, Kai-Uwe Hinrichs from the University of Bremen and Woods Hole Oceanographic Institution, and Andreas Teske from the University of North Carolina. The team included graduate students Biddle, Julius S. Lipp, Mark Lever and Karen Lloyd.

A’ndrea Elyse Messer | EurekAlert!
Further information:
http://www.psu.edu

More articles from Ecology, The Environment and Conservation:

nachricht How does the loss of species alter ecosystems?
18.05.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Excess diesel emissions bring global health & environmental impacts
16.05.2017 | International Institute for Applied Systems Analysis (IIASA)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

 
Latest News

Scientists propose synestia, a new type of planetary object

23.05.2017 | Physics and Astronomy

Zap! Graphene is bad news for bacteria

23.05.2017 | Life Sciences

Medical gamma-ray camera is now palm-sized

23.05.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>