Researchers on site rapidly after gas leak

A cancelled trip to Iceland and researchers who think outside the box. It meant that Katarina Abrahamsson and her colleagues could embark on an expedition aboard the research vessel Skagerak to the site of the Nord Stream gas leaks in the Baltic Sea only two days after their detection.

News about the huge methane gas leak in the Baltic Sea made headlines for several days in late September this year. Initial reports suggested that the unprecedented leak would probably not impact marine life in the area. It was believed that the gas would rise into the air at the water surface and create a temporarily enhanced greenhouse effect.

However, marine biologist Thomas Dahlgren from the Department of Marine Sciences had a different opinion.

“We know that high concentrations of natural gas are toxic to fish. In this area, I was thinking that Baltic cod would be those at risk, but that it would probably affect more species. The leak was probably going to be bad news for the Baltic Sea, which is a sensitive ecosystem,” explains Dahlgren, who received a lot of attention from the media for his warnings.

It’s a Thursday afternoon in early October. Dahlgren gets out of his car at Nya Varvet and walks down to the quay to meet the research vessel Skagerak following its expedition to the site of the Nord Stream gas leaks in the Baltic Sea. He is here to retrieve his underwater camera, which was bolted to the Rosette sampler, a kind of CTD device (measuring conductivity, temperature and depth).

Due to a postponed research expedition, the University’s research vessel Skagerak was available for the five-day expedition to the Southern Baltic Sea

“Unfortunately, I didn’t have the opportunity to go along myself. It’s going to be interesting to see what we find from the water samples taken. I must admit, it felt somewhat lonely being the only researcher to sound the alarm about the risks to marine life,” says Dahlgren.

The ship docked at 5:30 p.m. sharp and a dozen researchers signed off, exhausted after five intense days on board.

The methane gas leak was discovered on 26 September and for more than a week, methane gas leaked into the sea. Thanks to the rapid response of the researchers from the University of Gothenburg, they managed to reach the site before the discharge had completely stopped. Over a period of 54 hours, the expedition collected between 100 and 200 water samples.

“We set up 20 different measurement sites at intervals of about 9 to 18 kilometres to map the spread of the methane in the water. We had the help of researchers and equipment from the Alfred Wegener Institute in Germany. They can distinguish between methane from the natural gas pipeline and what occurs naturally,” says Professor Katarina Abrahamsson.

It was a happy coincidence that a planned research expedition to Iceland and the Faroe Islands had been cancelled due to severe weather. When the gas leak occurred, our new research vessel was in its home port, Nya Varvet. In record time, marine researchers from the University of Gothenburg organised an expedition led by Abrahamsson, who was able to use saved funding to pay for the expedition.

The measurements of the water at the site of the Nord Stream gas leak were immediately analysed in the Skagerak’s onboard laboratory.  

The determination of the researchers to get on their way before the leak had completely subsided was a crucial driving force as well.

 “There are many questions to be answered. Such as how much of the methane gas rises into the atmosphere and how much dissolves in the water,” Abrahamsson explains.

While on the expedition, the researchers were already able to establish that methane levels in the waters around the Nord Stream gas leak were 1,000 times higher than normal. The distribution pattern of the methane from the leak was complex and difficult to explain. One reason was that the expedition party was unable to measure the entire discharge, because the researchers were only allowed to survey Swedish waters. There was simply not enough time to apply for a permit from Denmark.

A month after returning home, much remains to be done before an analysis can be performed.

“Marine biologist Carina Bunse is working on the biological samples. They are not ready and it will take some time before they are. But we believe that much more methane dissolved in the water than was originally assumed. What happened to the methane in the water is unclear. Did bacteria take care of it, is it still there, or did it rise up into the atmosphere as the water was re-mixed?” Abrahamsson asks.

To answer all of these questions, Abrahamsson and her colleagues are planning a new expedition to the area east of Bornholm in January.

“It’s important to take follow-up measurements to understand what consequences the discharge will have in the future.” We hope we will be able to go, but the funding is yet to be secured. In the past, we could apply for emergency grants for research projects like this, and now it looks like that possibility is opening up for us. In that case, we will look at the plankton production and see if it might have been affected,” Abrahamsson explains.

Skagerak expedition to Nord Stream gas leaks

WHEN? 2 to 6 October. Departure was three days after the decision was made on the expedition.

WHERE? The surveys were conducted in the Southern Baltic Sea, east of Bornholm, in the Swedish economic zone.

WHY? To investigate the spread and potential impact on the marine environment of a historically massive discharge of methane gas from the Nord Stream pipelines on the sea floor.