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 Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland
15.11.2018 | Faculty of Science - University of Copenhagen

nachricht The unintended consequences of dams and reservoirs
14.11.2018 | Uppsala University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>