Expedition to the Faroe Islands to study Gulf Stream's counter current
Researchers from the University of Gothenburg are on their way to the Faroe Islands on the research vessel Skagerak. There they will map the cold counter currents of the Gulf Stream, which are of crucial importance for the climate in northern Europe.
The important Gulf Stream transports warm surface water northwards to the Arctic. But equally important for the global ocean circulation to work is the transport of cold deep water back south to the Atlantic – warmer surface water in, colder deep water out.
“We are going to the Faroe Islands to investigate the transport of cold deep water back to the Atlantic. It’s very important that we understand how the entire circulation works, as it affects the climate, both in Scandinavia and globally,” says Fabien Roquet, Professor of Oceanography, Department of Marine Sciences.
“Climate models predict that the circulation will weaken due to global warming, but this is something we can't really see yet in our observations. That's why we want to measure how it's changing – are the models incorrect, or are the changes just not yet visible in our measurements,” says Fabien Roquet.
Faroe Islands a key region
Changes in the circulation of seawater are closely linked to climate change in both the Arctic and the rest of the world, with the sea around the Faroe Islands a key region for understanding the circulation. This is because here are important deep-sea passages that transport cold deep water back towards the Atlantic.
Scientists are particularly interested in the paths that the water masses choose to take on their way south. One important passage is between the Faroe Islands and the Shetland Islands, but one aim of the expedition is to investigate whether the water also passes through a smaller and shallower passage between the Faroe Islands and Iceland.
“It is only 400 metres deep. It could be cold deep water going through that passage, but we don't really know, so we want to investigate it,” says Fabien Roquet.
Temperature and salinity affect circulation
The warm Gulf Stream is only a small part of the large Atlantic Ocean circulation system known as the AMOC – the Atlantic Meridional Overturning Circulation. For the circulation to work properly, the Gulf Stream’s warm surface water needs to cool down in the Arctic Ocean, raising the salinity and thus making the water heavier and denser. The water then sinks to the bottom of the ocean and flows back south towards the Atlantic again, making room for new warm surface water to appear.
During the expedition, the researchers will measure temperature, salinity and current speed, but also the movement of water all the way down to the seafloor. Both temperature and salinity affect the water's ability to circulate, and this can vary greatly over time. Mapping this area provides important pieces of the puzzle to understand how the ocean's large circulation system works.
“It’s very important to make continuous measurements over a long period of time to compare and detect changes. It’s a very inert system, and once it starts to change, it can affect the climate quite a lot,” says Fabien Roquet.
Writer: Annika Wall
Fabien Roquet is one of the researchers who have received funding for ship time from SWERVE, which is the Swedish Research Council's investment in ship infrastructure for marine research. The purpose of SWERVE is to provide Swedish marine researchers with improved access to ship and data infrastructure, and to support the training of a national network of marine technicians. Fabien Roquet's ship time is also funded with support from the Department of Marine Sciences, University of Gothenburg.
Fabien Roquet is leading the work between the Faroe and Shetland Islands. Léon Chafik from Stockholm University is leading the work between the Faroe Islands and Iceland.
The research team
Fabien Roquet, professor, University of Gothenburg
Anis El Youncha, researcher, University of Gothenburg
Leon Chafik, researcher, Stockholm University
Stefanie Semtner, researcher, Bergen University
Jakob Gunnarsson, PhD student, University of Gothenburg
Susanna Hentschel, Master’s student University of Gothenburg
Phil Krys, Master’s student, University of Gothenburg
Titouan Moulin, intern, University of Gothenburg
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