Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How Climate Change affects Microbial Life below the Seafloor

22.10.2013
Traces of past microbial life in sediments off the coast of Peru document how the microbial ecosystem under the seafloor has responded to climate change over hundreds of thousands of years.

For more a decade scientists at the Max Planck Institute for Marine Microbiology and their colleagues at MARUM and the University of Aarhus have investigated microbial life from this habitat.


The samples were taken during the Ocean Drilling Program (ODP) in 2002. (www-odp.tamu.edu).
NASA


The international drilling vessel JOIDES Resolution
iodp.org

This “Deep Biosphere”, reaching several hundred meters below the seafloor, is exclusively inhabited by microbes and is generally considered as stable. Nevertheless, only little is known about how this system developed over millennia and how this microbial life influences the cycling of carbon in the oceans.

In a new study appearing in the Proceedings of the National Academy of Sciences (PNAS) Dr. Sergio Contreras, a palaeoceanographer, and his Bremen colleagues use a careful examination of drill-cores from the continental shelf of Peru to actually show how surprisingly dynamic this deeply buried ecosystem can be.

Below the sea floor, consortia of two different domains of microorganisms (archaea and bacteria) tap the energy of methane, which they oxidize by using sulfate. This process is known as the anaerobic oxidation of methane (AOM) and has been intensively studied by Bremen researchers. Methane, also produced by archaea, emerges from deeper layers of the sediment, while sulfate diffuses slowly from the water column into the sediment.

Both reactants meet at the so-called methane oxidation front. Only at this front are concentrations of sulfate and methane high enough for the microbial turnover to take place, and here the AOM process leaves behind mineral and biological fossil signatures. For example, archaeol, a constituent of the archaeal cell membrane, is an extremely stable molecule that is preserved over thousands to millions of years. Minerals such as barite (barium sulfate) and dolomite (magnesium calcium carbonate) also precipitate at this methane oxidation front due to microbial activity.

Migration of the methane oxidation front
In order to trace the migration of the methane oxidation front back over the last half million years, Dr. Contreras and his colleagues measured the barite, dolomite and archaeol content at high resolution in drill cores from the coast off Peru. These up to 200-meter-long cores from the Peruvian continental shelf were obtained during an expedition with the scientific drill ship JOIDES Resolution as part of the Ocean Drilling Program in 2002. To their surprise, Contreras and his colleagues detected a layer that was strongly enriched in archaeol, barite and dolomite, located 20 meter above the present-day methane oxidation front. They estimated that this layer was formed during the last interglacial time period about 125000 years ago and that the methane front must have rapidly migrated downwards during the last glacial period. „Our data demonstrate how fast the microbial communities respond to changes in the oceanographic conditions, at least on a geological time scale“, explains the biogeochemist Dr. Tim Ferdelman.
Exploring the past with mathematical modeling
To reconstruct the rapid shifts in the depth of the methane front, Contreras and his colleagues used a mathematical model for simulating the deep microbial activity and its dependence on climate change. The simulations clearly show that the amount of organic detritus raining out from the highly productive Peruvian surface waters is the crucial factor determining the relative position of the methane front. The amount of carbon deposited on the Peruvian shelf strongly depends on the global climate; thus the methane oxidation front moved upwards during warm periods due to intensified organic carbon deposition, and migrated downwards with the onset of cold, glacial periods due to low organic carbon deposition. ”We can incorporate these new findings into models for the development of past or future Deep Biospheres“, concludes Dr. Bo Liu who developed the model for this study.

The geologist Dr. Patrick Meister highlights the implications of this finding: „The detected traces provide the key to the history of the sub-seafloor microbial activity and its dynamic interaction with climate and oceanography for of the past 100,000 years. If we look further back in time, such as over the past million years” speculates Meister, “we might find even more drastic changes of microbial activity in the deep biosphere“. Such ongoing research efforts between geologists and microbiologists, along with access to deep sediment samples within the framework of the Integrated Ocean Drilling Program (IODP), should continue to provide insight into the interactions between climate and the deep biosphere.

Further Informationen

Dr. Patrick Meister, +49 421 2028832, pmeister@mpi-bremen.de
Dr. Timothy Ferdelman, +49 421 2028632, tferdelm@mpi-bremen.de
Press officer
Dr. Manfred Schloesser, +49 421 2028704, mschloes@mpi-bremen.de
Original publication
Cyclic 100 ka (glacial-interglacial) migration of sub-seafloor redox zonation on the Peruvian shelf. Sergio Contreras, Patrick Meister, Bo Liu, Xavier Prieto-Mollar, Kai-Uwe Hinrichs, Arzhang Khalili, Timothy G. Ferdelman, Marcel M. M. Kuypers, and Bo Barker Jørgensen. Proceedings of the National Academy of Sciences, 2013.

doi/10.1073/pnas.1305981110

Institutes and Universities
Max Planck Institute for Marine Microbiology, Department of Biogeochemistry, Celsiusstrasse 1, D-28359 Bremen, Germany

Organic Geochemistry Group, MARUM - Center for Marine Environmental Sciences & Department of Geosciences, University of Bremen, D-28359 Bremen, Germany

Department of Bioscience, Center for Geomicrobiology, Aarhus University, Ny Munkegade 116, 8000 Aarhus C, Denmark.

Dr. Manfred Schloesser | Max-Planck-Institut
Further information:
http://www.mpi-bremen.de

More articles from Life Sciences:

nachricht New photocatalyst speeds up the conversion of carbon dioxide into chemical resources
29.05.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)

nachricht Copper hydroxide nanoparticles provide protection against toxic oxygen radicals in cigarette smoke
29.05.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | 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

 
Latest News

New insights into the ancestors of all complex life

29.05.2017 | Earth Sciences

New photocatalyst speeds up the conversion of carbon dioxide into chemical resources

29.05.2017 | Life Sciences

NASA's SDO sees partial eclipse in space

29.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>