Hot springs in the Arctic

Hydrothermal vents in the deep sea are considered hotspots of life. However, the search for them is comparable to the proverbial search for a needle in a haystack. It is known that such systems are formed on permeable structures, such as the spreading ridges of the Earth's plates. The Gakkel Ridge in the Arctic Ocean is the slowest-spreading mid-ocean ridge worldwide. Researchers on an expedition with the research icebreaker POLARSTERN discovered the northernmost hydrothermal field on Earth here – only around 300 kilometers from the North Pole.

Whereas black smokers, the best-known type of hydrothermal system, discharge metal-rich fluids the researchers at the newly discovered Polaris field used a combination of geochemical analyses and investigations of the seafloor to detect metal-poor fluids, but increased hydrogen and methane contents. “This discovery was unexpected,” says lead author Elmar Albers, who is now a researcher at the Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research. “Based on the geological features of the seafloor and the few earlier data from Polaris' hydrothermal plume, we assumed that we would find a system with black smokers.”

Starting from hydrothermal plumes in the water column, the researchers followed the trail to the ocean floor. Here they did not come across black smokers, but rather small-scale chimney structures. “It is the interactions of the hydrothermal fluids with the deeper-lying rocks that are responsible for Polaris' formation – and not the rocks directly on the seafloor,” explains Albers. “Geochemical data from hydrothermal fluids are essential to unravel the processes in the subsurface. There is no such data for the vast majority of hydrothermal fields on ultraslow-spreading ridges. Without it, misinterpretations can easily occur, as in the case of Polaris, with far-reaching consequences for the understanding of global material cycles, for example.”

The study not only contributes to even better research into the ocean floor. Moreover, NASA researchers see hydrothermal systems such as Polaris in the ice-covered Arctic as a possible direct counterpart to the systems on the ice-covered moons of other planetary bodies - on which hydrothermal vents could have made the origin of life possible, just like on Earth.

The expeditions and research on the Polaris Field were realized as part of the funding for the Cluster of Excellence “Ocean Floor – Earth’s Uncharted Interface”.

More information:

Polaris background information from WHOI: https://www.whoi.edu/press-room/news-release/polaris-site/

Participating institutions:

• MARUM – Center for Marine Environmental Sciences at the University of Bremen
• Faculty of Geosciences at the University of Bremen
• Department of Geology & Geophysics, Woods Hole Oceanographic Institution (USA)
• Department of Marine Chemistry & Geochemistry, Woods Hole Oceanographic Institution (USA)
• Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research
• Max Planck Institute for Marine Microbiology Bremen
• Institute for Environmental Physics, University of Bremen
• Department of Earth and Environmental Sciences, Lehigh University (USA)
• Department of Oceanography, Texas A&M University (USA)
• Polar Science Center, Applied Physics Lab, University of Washington (USA)