Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

More methane from the deep sea: Mud-volcanoes as methane source

11.11.2014

The mud-volcano Haakon Mosby in the Barents sea near Norway emits yearly several hundred tons of methane, a potent greenhouse gas. A research team, coordinated by the Max-Planck-Institute in Bremen, reports on the results of a long-term observatory in NATURE Communications.

They collected during 431 days data on temperature, pressure and pH and documented using a camera 25 eruptions of mud and gas. Some of these eruptions were so violent that the seabed topography was profoundly changed. They calculated that the mud-volcano may emit 10 times more methane than previously assumed.


Scheme of the mudvolcano. It has a diameter of 1 kilometer but an elevation of only 10 meter. The arrows indicate the mud movements. M. Schloesser, MPI Bremen


LOOME (Long Term Observatory On Mud-volcano Eruptions) made observations on the Haakon Mosby Mud Volcano during 431 days. Dirk de Beer, MPI Bremen

There are over 1000 terrestrial mud-volcanos known, and a growing number is found in the sea, between 200 and 4000 m depth, such as the Haakon Mosby Mud Volcano. Scientists estimated that the submarine volcanos emit 27 Million tons of methane, which is about 5% of the global emission. This may be an underestimation, as not all volcanoes are found and because they are not monitored by long term observatories.

The rhythm of mud-volcanoes
The question is whether submarine mud-volcanoes emit gas and mud continuously or if they have now and then an outburst? In a steady state a continuous of gaseous mud flows through the chimney from large depth. A part of the gas goes into the seawater, and a part is microbially converted in the sediments. While assuming a steady flow scientists have calculated the emission and conversion rates. Eruptions have never been observed during visits with research vessels. To see such rare events, permanent observations are needed. Such an instrument was developed and used by the team of scientist led by Dr. Dirk de Beer.

A biological methane filter
It is believed that a large part of the methane does not reach the atmosphere, because it is mostly microbially converted to CO2 in the seabottom. This oxidation is driven by sulfate, by very slow growing bacteria that divide every 3-6 months. This microbial filter is therefore very sensitive for disturbances by eruptions. The microbial filter works only efficiently when the gas flow is slow and steady. When the gas flows fast, it will simply pass the filter into the water column. An eruption would perturb the sediment and the filter gets totally destroyed.

The long-term observatory
To see the occurrence and frequency of eruptions, the scientists placed a platform with a variety of sensors on the Haakon Mosby Mud Volcano at 1200 meter depth. The volcano has a diameter of 1 kilometer and an elevation of only 10 m. While the bottom water is ice-cold, inside the sediment the temperature increases rapidly. Dr. Tom Feseker (MARUM center for marine environmental sciences, University of Bremen): „We measured in the center of the volcano at 1 meter depth a temperature of 25oC. The heat is carried from large depth by gas-rich fluids. “

The scientists aimed with the LOOME observatory to find out if the gas hydrates in the seabottom could be disintegrated by this heat. In 2009 LOOME was deployed by the deep sea robot Quest (MARUM). The sensors were placed on the most active area, connected by cables to the observatory. The thermometers showed several heat pulses, gas was liberated and elevated the seabottom in pulses by over 1 meter. The sediments slipped sideways over several hunderds of meters. After the series of eruptions, the seabottom subsided gradually to its original elevation.

10 times more methane than thought
Dr. Dirk de Beer from the Max-Planck-Institute for Marine Microbiology and scientific leader of the LOOME project explains: „The eruptions are driven by gas that originates from large depths. Also the heat destabilizes the gas hydrates in the surface of the volcano and the methane gets liberated. The gas reaches finally the water column. We calculated that to drive these eruptions at least 10 times more gas is emitted that previously assumed. Most of the gas may not reach the atmosphere, but gets diluted in the seawater where it can be oxidized by aerobic bacteria.“

A study of the bathymetric maps made since 2003 showed indeed drastic changes of the seabottom topography. Remarkably, no signs were observed of mud flowing out of the volcano. That means that the moving mud is recycled inside the volcano. The horizontal movement of the mud could precisely be reconstructed, as a 20 m long and 2 ton heavy temperature lance moved in the year a distance of 165 m.

An important conclusion of the study is that the microbial filter is destroyed regularly by the eruptions, and has no time to grow back in between. Prof. Dr. Antje Boetius, cruise leader during deployment and recovery, says: „We have learned a lot from the year-long observations. As it was the first in its kind, we got unique data on the volcano and its influence on the environment. Since eruptions of such volcanoes can cause large avalanches and form significant sources of methane, we should deploy more long-term observatories.“

Manfred Schlösser

Request for information:
Dr. Dirk de Beer, Max-Planck-Institute for Marine Microbiology, Tel. +49 421 2028 802,
dbeer@mpi-bremen.de

Dr. Tom Feseker, MARUM, feseker@uni-bremen.de

Prof. Dr. Antje Boetius, Alfred –Wegener-Institute and Max-Planck-Institut for Marine Microbiology, Tel. +49 421 2028 860, antje.boetius@awi.de

Or the PR person:
Dr. Manfred Schloesser, Max-Planck-Institut for Marine Microbiology, Tel.: 0421 2028704, mschloes@mpi-bremen.de,
Original title:
Eruption of a deep-sea mud volcano triggers rapid sediment movement
Tomas Feseker, Antje Boetius, Frank Wenzhöfer, Jerome Blandin, Karine Olu, Dana R. Yoerger, Richard Camilli, Christopher R. German, Dirk de Beer.
Nature Communications, November 2014, DOI: NCOMMS6385

Contributing institutes
Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany
MARUM - Center for Marine Environmental Sciences and Faculty of Geosciences, University of Bremen, 28359 Bremen, Germany
GEOMAR, Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Germany
HGF-MPG Group for Deep Sea Ecology and Technology, Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association, 27515 Bremerhaven, Germany
IFREMER, Institut Carnot EDROME, RDT/ SI2M F-29280 Plouzané, France
IFREMER, Institut Carnot EDROME, REM/EEP, Laboratoire Environnement Profond, F-29280 Plouzané, France
Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA

Acknowledgements: LOOME was paid via the EU program ESONET, the Helmholtz Foundation, the Max-Planck-Society and the Leibniz-programm of the DFG.


Weitere Informationen:

http://www.mpi-bremen.de/Forschung_am_Tiefsee-Schlammvulkan_Haakon_Mosby.html
http://www.esonet-emso.org/  (Webseite Europäischer Meeresboden Observatorien)

Dr. Manfred Schloesser | Max-Planck-Institut

More articles from Earth Sciences:

nachricht New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz

nachricht Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>