Monitoring the Nord Stream Gas Leak

13 December, 2022

On September 26th, both Nord Stream gas pipes ruptured, leading to enormous gas leaks outside of Bornholm in the Baltic Sea. Voice of the Ocean Foundation and University of Gothenburg quickly set up operations to monitor both what was happening from an oceanographic point of view, and also the methane directly. To see how it spread and how it remained over time. 

Within five days, multiple gliders were deployed to gather ocean data in the area. The gliders are ideal for gathering data in remote areas and under almost any weather conditions. After deployment, the glider takes measurements of water properties while moving up and down in a sawtooth pattern.  

graphic map
Graphics by Martin Mohrmann, data from Voice of the Ocean Foundation, GU, E.U. Copernicus Marine Service Information and Alseamar

– We’re proud to be able to support projects like these, where the quick response, professionalism and expertise of our operations team means we can capture critical data soon after an environmental event, says Dr Louise Biddle, Head of Science VOTO 

The gas emitted from the leak is natural gas, which contains high levels of methane. Methane gas is one of the greenhouse gases. Greenhouse gases act as insulation for the Earth, trapping heat from the sun so that the Earth is livable. Methane gas is produced naturally through decomposition. Yet, since humans started using it as fuel, the amount dispersed into the atmosphere has multiplied several times and is a major driver for anthropogenic climate change. The size of the Nordstream leak was equivalent to Sweden’s yearly output.  

More than the gas itself, researchers at VOTO also witnessed the effect of bubbles coming up to the surface, mixing cold salty water from the bottom, with warmer and less salty waters above. Think of it as when you are opening a bottle of carbonated water. The bubbles formed at the bottom will seek their way toward the surface. In the process, it will push the water around it, creating movement. Mixing of the surface water and deeper water happens naturally with the help of winds and currents. But this time, it was more dramatic and quick. Mixing the different “layers” changes the properties (such as salinity, temperature, nutrients, and gases) of the water both at the surface and closer to the bottom.  Mixing is particularly important in the Baltic Sea because the water naturally has very separate layers. The bottom contains little oxygen, limiting what organisms can live there.  

Researchers also believes that it is important to monitor the area around the Nord Stream leaks from an oceanographic and environmental point of view. In the near future, we will need to understand if and how the leak impacted our environment.  

– I’m excited to see such clear results coming in – we had to start this project in a rush to react quickly and it can be tricky to get things right. VOTO have been able to keep the gliders there continuously which has really revealed the change in methane concentrations, says Dr Bastien Queste, Associate senior lecturer in oceanography at the University of Gothenburg 

We have collected and shared the data via our open-source observations portal for any interested researchers.  

Text: Ville Engberg, VOTO
Photo: Aleksandra Mazur, Oceanograf på Voice of the Ocean
Graphics: Martin Mohrmann

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