The Borealis Mud Volcano in the Barents Sea was first discovered in 2023 by researchers from UiT – The Arctic University of Norway and was visited again in 2024 with the Norwegian research vessel RV Kronprins Haakon. An international team of scientists participated in the expeditions and in the subsequent studies on the collected data and samples from the seafloor.
This mud volcano structure, located in the Barents Sea in the Polar North Atlantic, is distinct from previously identified methane seepages in the region and is the second mud volcano structure discovered this far north.
The volcano is nearly 300m wide and 25m deep. Inside the crater, there is a roughly 7-meter-diameter and 2.5-meter-high active 'mud gryphon' that continuously emits mud and methane-rich fluids.
Researcher Adriano Mazzini from University of Oslo and Institute for Energy Technology (IFE) was part of the team that studied the unique seafloor observations and samples collected after the expeditions. The findings of the studies from the Borealis Mud Volcano is now published in Nature Communications.
Carbonate deposits around the mud volcano
Using an underwater remotely operated vehicle (ROV) operated from the research vessel, the scientists discovered that the methane seepage broadly distributed throughout the mud volcano surface prompted the diffuse precipitation of 'methanogenic' carbonates.
– The precipitation of "methanogenic" carbonates has been going on for a long time and has paved the whole seafloor of this large structure,' says Adriano Mazzini, a specialist on mud volcanoes and one of the authors of the new study.
The Barents Sea and the Norwegian continental shelf feature thousands of natural methane seepage sites.
However, the Borealis Mud Volcano is just the second structure of such type to be discovered in the Barents Sea, revealing that this region still hides many secrets to be uncovered.
– I would not be surprised if more mud volcanoes are discovered in the future. We already have evidence of thousands of methane seeps in the region, and this vast hydrocarbon province has all the characteristics needed to promote the manifestation of this type of geological phenomenon," says Adriano Mazzini.
Important refuge for endangered species
Studies of the mud volcano on the seafloor of the Barents Sea in the Atlantic Ocean show that it hosts unique species adapted to low-oxygen environments near methane seeps. Furthermore, laterally extensive carbonate deposits on the seafloor act as nursery grounds for endangered fish species.
These crucial habitats for sessile fauna serve as a natural sanctuary for unique species, including the redfish (Sebastes marinus), a species listed as endangered in Norway. The carbonate deposits protect them from bottom trawling.
The findings underscore the ecological significance of cold seep ecosystems in the Polar North Atlantic, according to the researchers.
– These seeping systems play an essential role in marine biodiversity by offering refuge and habitats for various marine species. The protection of such sites along the Norwegian margin is essential for the wider recolonization and restoration of benthic biological communities, according to our research, concludes Mazzini.
The scientific article
Panieri, G., Argentino, C., Savini, A. et al. Sanctuary for vulnerable Arctic species at the Borealis Mud Volcano. Nat Commun 16, 504 (2025). https://doi.org/10.1038/s41467-024-55712-x
Research: The WellFate project
Researcher Dr. Adriano Mazzini, Dept of Geosciences, University of Oslo and IFE is a part of the WellFate project at IFE that aims to investigate the migration mechanisms of methane through the sedimentary strata, the water column and eventually at the surface. Read more about the WellFate project here.
More about the mud volcano
New Discovery in the Arctic Ocean: Borealis Mud Volcano, Institute for Energy Technology (IFE), Norway
Underwater mud volcanos are a haven for marine organisms, UiT The Arctic University of Norway.