Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Wandering greenhouse gas

16.03.2018

Climate models need to take into account the interaction between methane, the Arctic Ocean and ice

On the seafloor of the shallow coastal regions north of Siberia, microorganisms produce methane when they break down plant remains. If this greenhouse gas finds its way into the water, it can also become trapped in the sea ice that forms in these coastal waters.


German scientists from the area of biogeochemistry from the Alfred Wegener Institute at work. On a small area on which they drill through the ice with a hollow borer, they take ice cores and sawed them into short pieces, representing the layers of the ice surface to the bottom. These migrate well documented in bags and are analyzed on the ship by different groups. After thawing, a core is filtered to determine the amount of ice algae, for example. (Photo: Stefan Hendricks)

As a result, the gas can be transported thousands of kilometres across the Arctic Ocean and released in a completely different region months later. This phenomenon is the subject of an article by researchers from the Alfred Wegener Institute, published in the current issue of the online journal Scientific Reports. Although this interaction between methane, ocean and ice has a significant influence on climate change, to date it has not been reflected in climate models.

In August 2011, the icebreaker Polarstern from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) was making its way through the ice-covered Arctic Ocean, on a course that took her just a few hundred kilometres from the North Pole.

Back then, AWI geochemist Dr Ellen Damm tested the waters of the High North for the greenhouse gas methane. In an expedition to the same region four years later, she had the chance to compare the measurements taken at different times, and found significantly less methane in the water samples.

Ellen Damm, together with Dr Dorothea Bauch from the GEOMAR Helmholtz Centre for Ocean Research in Kiel and other colleagues, analysed the samples to determine the regional levels of methane, and the sources. By measuring the oxygen isotopes in the sea ice, the scientists were able to deduce where and when the ice was formed. To do so, they had also taken sea-ice samples.

Their findings: the ice transports the methane across the Arctic Ocean. And it appears to do so differently every year, as the two researchers and their colleagues from the AWI, the Finnish Meteorological Institute in Helsinki and the Russian Academy of Science in Moscow relate in the online journal Scientific Reports.

The samples from 2011 came from sea ice that had started its long journey north in the coastal waters of the Laptev Sea of eastern Siberia nearly two years earlier, in October 2009. The samples from 2015, which had only been underway in the Arctic Ocean half as long, showed a markedly lower level of the greenhouse gas. The analysis revealed that this ice was formed much farther out, in the deeper ocean waters. However, until now, the climate researchers’ models haven’t taken into consideration the interaction between methane, the Arctic Ocean and the ice floating on it.

Every molecule of methane in the air has 25 times the effect on temperature rise compared to a molecule of carbon dioxide released into the atmosphere by burning coal, oil or gas. Methane in the Arctic also has an enormous impact on warming at northerly latitudes, and further exacerbates global warming – a good reason to investigate the methane cycle in the High North more closely.

Methane is produced by cattle breeding and rice cultivation, as well as various other natural processes. For example, the remains of algae and other plant materials collect on the floor of the shallow Laptev Sea, and in other shallow waters off the Arctic coast. If there is no oxygen there, microorganisms break down this biomass, producing methane. To date, simulations have paid too little attention to the routes of by carbon and release of methane from the Arctic regions.

In autumn, when air temperatures drop, many areas of open water also begin to cool. “Sea ice forms on the surface of the Russian shelf seas, and is then driven north by the strong winds,” explains AWI sea-ice physicist Dr Thomas Krumpen, who also took part in the study. The ice formation and offshore winds produce strong currents in these shallow marginal seas, which stir up the sediment and carry the methane produced there into the water column. The methane can also be trapped in the ice that rapidly forms in these open areas of water – also known as polynya – in the winter.

“As more seawater freezes it can expel the brine contained within, entraining large quantities of the methane locked in the ice,” explains AWI researcher Ellen Damm. As a result, a water-layer is formed beneath the ice that contains large amounts of both salt and methane. Yet the ice on the surface and the dense saltwater below, together with the greenhouse gas it contains, are all pushed on by the wind and currents. According to Thomas Krumpen, “It takes about two and a half years for the ice formed along the coast of the Laptev Sea to be carried across the Arctic Ocean and past the North Pole into the Fram Strait between the east cost of Greenland and Svalbard.” Needless to say, the methane trapped in the ice and the underlying saltwater is along for the ride.

The rising temperatures produced by climate change are increasingly melting this ice. Both the area of water covered by sea ice and the thickness of the ice have been decreasing in recent years, and thinner ice is blown farther and faster by the wind. “In the past few years, we’ve observed that ice is carried across the Arctic Ocean faster and faster,” confirms Thomas Krumpen. And this process naturally means major changes in the Arctic’s methane turnover. Accordingly, quantifying the sources, sinks and transport routes of methane in the Arctic continues to represent a considerable challenge for the scientific community.

Original Publication:
Damm, E., Bauch, D., Krumpen, T., Rabe, B., Korhonen, M., Vinogradova, E. and Uhlig, C.: “The Transpolar Drift conveys methane from the Siberian Shelf to the central Arctic Ocean”. Scientific Reports 2018. DOI: 10.1038/s41598-018-22801-z (https://www.nature.com/articles/s41598-018-22801-z)

Notes for Editors

Printable images are available at: https://www.awi.de/nc/en/about-us/service/press/press-release/wandering-greenhou...

Your scientific contact persons are:

Dr Ellen Damm, tel. +49 (0)471 4831-1423 (e-mail: Ellen.Damm(at)awi.de); today (Friday, 16 March) at tel. +49 (0)331 288 20109

Dr Thomas Krumpen, tel. +49 (0)471 4831-1753 (e-mail: Thomas.Krumpen(at)awi.de)

Your contact person at the Dept. of Communications and Media Relations is Dr Folke Mehrtens. tel. +49 (0)471 4831-2007 (e-mail: Folke.Mehrtens(at)awi.de).

Follow the Alfred Wegener Institute on Twitter (https://twitter.com/AWI_Media) and Facebook (www.facebook.com/AlfredWegenerInstitute).

The Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) conducts research in the Arctic, Antarctic and oceans of the high and mid-latitudes. It coordinates polar research in Germany and provides major infrastructure to the international scientific community, such as the research icebreaker Polarstern and stations in the Arctic and Antarctica. 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

More articles from Earth Sciences:

nachricht Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle
22.06.2018 | Technical University of Denmark

nachricht Polar ice may be softer than we thought
22.06.2018 | Eberhard Karls Universität Tübingen

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>