Swedish scientists on their way to the Nord Stream leak

09 January, 2023

With a large number of sampling bottles and special equipment from Germany, researchers from the University of Gothenburg are now on the Baltic Sea. The aim is to investigate the levels of methane gas following the Nord Stream leak and to find out the consequences for marine life.

– We hope to take samples at 40 different locations and get a picture of how the methane gas has spread,” says Katarina Abrahamsson, Professor of Analytical and Marine Chemistry at the University of Gothenburg and coordinator of the expedition.

TT reaches her half an hour after the ship Skagerak left Gothenburg. On board are eight scientists, one technician and a crew of seven. For a week, they will be taking water samples in the Baltic Sea to analyze both the extent of the gas and whether the spill has affected wildlife and aquatic life.
In the past, methane levels have been 1,000 times higher than normal in the vicinity of the Nord Stream pipeline leaks.

Can collect freely

Katarina Abrahamsson was one of the researchers on a similar expedition just a week after the explosions that caused the leak. At that time, they were unable to take samples as they wished because, among other things, they had not had time to apply for permission to sample Danish water.

– Now we have virtually no restrictions, which will give us a better picture,” says Katarina Abrahamsson.

The researchers use a sampling system that, in simple terms, consists of a large number of bottles that can be closed at different depths. At each stop, water is collected at up to five different depths, from the surface to about 70 metres below.

Once on the ship, the researchers can quickly get answers about methane content and acidity, for example. They can also find out the source of the methane.

– Methane is naturally present throughout the Baltic Sea, but with the help of special equipment brought by our German colleagues, we can get an indication of whether it is coming from the leak or from something else. This is very important to be able to draw conclusions about the impact of the spill.

May have filled up with gas

Some samples are taken home to be examined in the lab by marine biologists. They allow scientists to find out how the composition of plankton and bacteria has been affected. But those answers take up to a couple of months to analyze.

What effect the high levels of methane might have on marine life is unclear. There are bacteria in the water that can oxidize methane gas to grow and multiply. If the methane-eating bacteria are growing at the expense of other plankton species, this could affect life below the surface locally.

According to Katarina Abrahamsson, they will also be able to see if methane continues to leak from the pipeline.

– There’s a theory that natural gas may have been added to prevent too much salt water from entering the pipeline. We don’t know if that’s true, but if it is, we’ll know.

The ship is scheduled to be back in Gothenburg on Saturday 14 January.
Petra Hedbom/TT

At the end of September, four leaks were discovered on the Nord Stream 1 and 2 gas pipelines running from Russia to Germany through the Baltic Sea.
Two of the leaks are in the Swedish economic zone, north-east of Bornholm, and two in the Danish economic zone, south-east of Bornholm. Countries’ economic zones are not the same as territorial waters.
Both Swedish and Danish seismic measurements show that explosions took place in the sea a few hours before each leak was discovered.
Authorities and assessors in several countries were quick to suggest that the attacks were deliberate.
On 18 November, Swedish prosecutors confirmed that the pipelines had been subjected to serious sabotage.

Text: Petra Hedbom, TT
Photo: Olof Lönnehed, University of Gothenburg

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