Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Leakage on the continental margin


Gas seepage off Norwegian coast spans hundreds of kilometers

Off the coast of Spitsbergen, on the upper continental margin between Bear Island and Kongsfjord, methane gas is emitted from the seafloor at more than a thousand sites. Past expeditions have reported methane gas seeps off the coast of Prins Karls Forland, presumed by some scientists to be a result of the dissociation of methane hydrates in the sediments caused by warming in recent years.

The Research Vessel HEINCKE at the pier at Ny-Ålesund.

Photo: G. Bohrman/MARUM-Center for Marine Environmental Sciences, University of Bremen

Team members sample water for methane analysis.

Photo: G. Bohrman/MARUM-Center for Marine Environmental Sciences, University of Bremen

The results of two cruises of the Research Vessel HEINCKE in 2015 have revealed, however, that methane emissions are not limited to this site, but extend across five degrees of latitude along the continental margin, and is very likely associated with the Hornsund Fracture Zone. Susan Mau has now published the results together with her colleagues at MARUM – Center for Marine Environmental Sciences at the University of Bremen, and others from the Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung in Bremerhaven and Oregon State University (USA).

The investigations of Susan Mau and her colleagues are based on data from two research cruises in the summer of 2015. The gas discharge sites were identified hydroacoustically as patterns called “flares.” “We already knew about the gas seeps off Prins Karls Forland because that site has been thoroughly studied,” explains Dr. Mau.

Their data, however, reveal the presence of numerous emission sites along the entire coast. The sites follow a fracture zone on the upper continental margin that could be the conduit for the methane rising from depths along this zone. Like air from a perforated bicycle inner tube submerged in water, the rising gas can escape along the fractures and ascend through the sea water. According to Mau, the scientists measured consistently high methane concentrations along the entire slope off the coast of Svalbard. “But they were especially high at the sites where multiple flares were seen.”

In addition, the gas seepage conspicuously occurred at bathymetrically elevated areas rather than in the troughs between them. Susan Mau presumes the reason for this is fine-grained deposits sealing the pathways that gas could otherwise escape from.

Why have so many emission sites been discovered off Prins Karls Forland? Are there even more sites off the coast of Svalbard? These were the initial questions to be addressed by the cruises led by Susan Mau and Gerhard Bohrmann. Furthermore, rock samples and seismic studies have shown that the entire coast is characterized by similar tectonic conditions and glacial history. The gas seeps verified off the coast of Svalbard are interesting primarily because scientists have thought that the methane escaping here is released from methane hydrates. Methane hydrates have a solid ice-like structure that is only stable under specific pressure conditions at rather well defined depths and relatively low temperatures. When the water becomes warmer methane hydrate is no longer stable and methane is released.

Should the water warm up – due to climate change, for example – methane hydrates can only occur in deeper sediments. The boundary zone in which gas hydrates become stable is effectively shifted downward. The gas bubble emissions observed by Mau and her colleagues, however, also occur above this boundary, and thus are not anthropogenically triggered gas released from methane hydrates.

These methane seepage sites are the result, rather, of large amounts of gas from great depths escaping along the Hornsund Fracture Zone, an extensive fault zone in the Earth’s crust, a natural geologic process. This produces high gas concentrations that the team has confirmed over a range of hundreds of kilometers along the coast. The data from the summer of 2015 also indicate that the dissolved methane is oxidized by microbes within the water column and only a small proportion escapes into the atmosphere. The microbes thus prevent an increase in greenhouse gas concentrations in the atmosphere.

From their current results, numerous new questions arise for the geologists Susan Mau and Gerhard Bohrmann: What is the precise course of the actual fracture zone? What is the character of the substratum? Where are the gas reservoirs located? And: What is the age of the escaping gas? In any case, a connection between the large number of gas seeps and human-produced warming of the oceans has not been confirmed.

Because the expeditions off the coast by Mau and her colleagues were carried out in the summer, it is not certain what happens during other colder and stormier seasons. “Our results cry out for long-term studies of the seeps,” Mau emphasizes. “We have to strive to learn the reason for high methane gas concentrations that have occurred repeatedly throughout the Earth’s history. The goal is to observe the seepage sites to find out what happens over the course of the year. Only then will it be possible to draw accurate conclusions – including, for example, whether gas emissions at these depths and at this temperate zone are climate relevant.”

Dr. Susan Mau
Telephone: +49 (0) 421-21865059

Original publication:
Susan Mau, Miriam Römer, Martha E. Torres, Ingeburg Bussmann, Thomas Pape, Ellen Damm, Patrizia Geprägs, Paul Wintersteller, Chieh-Wei Hsu, Markus Loher und Gerhard Bohrmann: Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden. Sci. Rep. 7, 42997; doi: 10.1038/srep42997 (2017)

Further information / Photo material:
Ulrike Prange
Telephone: 0421 218 65540

Weitere Informationen:

Ulrike Prange | idw - Informationsdienst Wissenschaft

More articles from Life Sciences:

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

nachricht Pollen taxi for bacteria
18.07.2018 | Technische Universität München

All articles from Life 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 >>>



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

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

Science & Research
Overview of more VideoLinks >>>