Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Sea Ice Plays a Pivotal Role in the Arctic Methane Cycle


Nature study on greenhouse gas feedback mechanisms between the atmosphere, sea ice and ocean

The ice-covered Arctic Ocean is a more important factor concerning the concentration of the greenhouse gas methane in the atmosphere than previously assumed. Experts from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) report on the newly discovered interactions between the atmosphere, sea ice and the ocean in a recent online study in the journal Nature’s Scientific Reports.

Installation of under-ice sensors during an ice station

Photo: Alfred-Wegener-Institut / S. Hendricks

Sea ice forms a natural barrier on the Central Arctic Ocean, limiting gas exchange between water and atmosphere. Over the past several years, the summer sea ice cover in the Arctic has rapidly decreased. “We’re investigating how the changed conditions are affecting the geochemical interaction between the ocean, ice and atmosphere,” explains Dr Ellen Damm, the first author of the study and a biogeochemist at the Alfred Wegener Institute.

“We were able to confirm that the surface water in the central Arctic contains higher methane concentrations than the atmosphere, which means the Arctic Ocean is a potential source of atmospheric methane. That makes it fundamentally different from oceans in lower latitudes, which – except for a few sporadic sources – are considered methane sinks.”

For the study, Damm and her colleagues from the AWI, the Finnish Meteorological Institute and the University of Bremen analysed geochemical and oceanographic data gathered during a 2011 expedition to the Arctic with the research icebreaker Polarstern. They measured methane levels in both the sea ice and in the water directly below it, and in deeper seawater entirely unaffected by the ice.

“Our study shows that there are previously overlooked feedbacks between ice melting and formation, the atmosphere, and the seawater influenced by ice,” says Damm.

Among other factors, they analysed the salt solution, i.e. the brine, which is constitutes concentrated seawater resulting during the formation of sea ice. They found that the brine had a thousand times higher concentration of methane than the atmosphere – proof that sea ice can be a source of methane.

As a result of the melting and freezing processes, methane in the brine channels can be released into the seawater. Further, the water remains in stable layers, due to the different densities of freshwater and saltwater. As such, the methane from the brine channels remains in the uppermost water layer throughout the summer.

When autumn storms set in and it gets colder, different water layers become mixed (convection), which can release the greenhouse gas into the atmosphere. At that time of year the sea ice cover is fragmented and the “lid” on the ocean has almost disappeared, conditions that are conducive to the release of methane into the atmosphere. The convection-based mixing continues in the winter, and methane continues to escape through the leads between ice floes.

The stable water layers prevent the methane from mixing to greater depths of the Arctic Ocean; the significantly lower methane concentrations (compared to the atmosphere) in the lower layer unaffected by the ice, verify this process. This has two effects: firstly, the newly discovered and as such not previously accounted for near-surface feedback mechanism can lead to the direct release of methane from the sea ice and ocean into the atmosphere.

Secondly, the exchange between atmosphere and the deeper Arctic Ocean is reduced, which also limits the Arctic Ocean’s capacity to act as a methane sink. Co-author and AWI oceanographer Prof Ursula Schauer summarises the study’s importance as follows: “The role of sea ice in gas exchange and gas flux is much more complex than previously assumed, and the processes at work in the Northern Ocean differ greatly from those in lower latitudes. These aspects have to be kept in mind in future climate models.”

Further, she points out, the study raises the question on where the methane originates. Conceivably, methane could be produced in sea ice as it drifts through the Arctic, or methane trapped in sea ice could be transported from other regions.

Original publication:
Ellen Damm, Bert Rudels, Ursula Schauer, Susan Mau and Gerhard Dieckmann: Methane excess in Arctic surface water-triggered by sea ice formation and melting. Nature online: Scientific Reports | 5:16179 | DOI: 10.1038/srep16179

Notes for Editors:

Please find printable images on Your contact persons are Dr Ellen Damm (tel. ++49 471 4831-1423; e-mail: Ellen.Damm(at) and Dr Folke Mehrtens, Dept. of Communications and Media Relations (tel. ++49 471 4831-2007; e-mail: Folke.Mehrtens(at)

The Alfred Wegener Institute conducts research in the Arctic, Antarctic and in the high and mid-latitude oceans. The Institute coordinates German polar research and provides important infrastructure such as the research icebreaker Polarstern and research stations in the Arctic and Antarctic to the national and international scientific world. The Alfred Wegener Institute is one of the 18 research centres of the Helmholtz Association, the largest scientific organisation in Germany.

Ralf Röchert | idw - Informationsdienst Wissenschaft
Further information:

More articles from Earth Sciences:

nachricht Wandering greenhouse gas
16.03.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht Unique Insights into the Antarctic Ice Shelf System
14.03.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

A new kind of quantum bits in two dimensions

19.03.2018 | Physics and Astronomy

Scientists have a new way to gauge the growth of nanowires

19.03.2018 | Materials Sciences

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Science & Research
Overview of more VideoLinks >>>