Nord Stream
Measuring Methane in the Baltic
AWI supports evaluation of the gas leak in the Nord Stream pipeline
[18. October 2022]
On 26 September, the operators of Nord Stream reported multiple gas leaks in the underwater pipeline. After consulting with the University of Göteborg and the responsible authorities, and after just three days of preparation, a Swedish and German research group led by Katarina Abrahamson departed on a five-day expedition to the site of the leak on board the research vessel Skagerak. Ellen Damm, Samuel Sellmaier and Volkmar Assmann from the Alfred Wegener Institute were on board to determine how much of the methane released was still in the waters of the Baltic.
The research was conducted at the edge of the restricted area to the north and northeast of the island Bornholm in Swedish waters, roughly seven nautical miles from the leak site. So as to have background values for comparison, the team collected part of their data on the way to the site, outside the contaminated area. At 20 different points, they collected 100 –120 water samples. What they found: a methane concentration approximately 10,000 times higher than ambient in the immediate vicinity of the leak. The farther away from the leak they checked, the more the gas concentration gradually declined, which can be attributed to its dissipating after spreading in the seawater.
Experts from the University of Göteborg conducted the oceanographic survey and gathered microbiological samples. In turn, the team led by geochemist Ellen Damm from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) was responsible for measuring the methane. “The measurements were taken directly on board. As such, the raw data is already available.” She adds: “In between sampling sites, we used our Picarro gas analysis unit to gather air samples. These automatic measurements offered us valuable atmospheric data.” The final results, expected to be available sometime in the next two weeks, will be combined with the oceanographic data. The chemical and physical oceanographic data will allow conclusions to be drawn concerning methane transport and what happens to the gas in the water.
One important goal of the expedition was to gauge the potential effects of the methane leak on organisms in the ocean and atmosphere. As Damm explains: “Microorganisms can feed on methane. As such, ideally the leak could produce increased microbial activity, which would lead to partial absorption of the gas.”
When it comes to how much gas has already been released into the atmosphere, and to whether there could be other leaks to the atmosphere when e.g. storms occur, further research is needed. “That completely depends on the meteorological conditions,” says Damm. “The question of which happens faster – the gas being released into the atmosphere, or microbial consumption in the water – is critical for how the escaping methane affects the climate.” At the same time as the ship-based expedition, there were two helicopter-based methane-measuring flights, coordinated by the Technische Universität Braunschweig and the German Aerospace Center (DLR).
A second expedition is planned for early December. In a subsequent evaluation of the gas leaks in the Nord Stream pipeline, Damm hopes to create a time series to facilitate the modelling of such events and help respond to such situations faster in future.
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