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 Safeguarding sustainability through forest certification mapping
27.06.2017 | International Institute for Applied Systems Analysis (IIASA)

nachricht Dune ecosystem modelling
26.06.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

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: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Touch Displays WAY-AX and WAY-DX by WayCon

27.06.2017 | Power and Electrical Engineering

Drones that drive

27.06.2017 | Information Technology

Ultra-compact phase modulators based on graphene plasmons

27.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>