Exploration of newly discovered hydrothermal vents at depths of 3000 meters off Svalbard

Hydrothermal vents can be found around the world at the junctions of drifting tectonic plates. But many hydrothermal fields remain to be discovered. During the MARIA S. MERIAN expedition in 2022, the first field of hydrothermal vents was discovered on the 500-kilometer-long Knipovich Ridge off the coast of Svalbard.

An international team of researchers from Bremen and Norway, led by Professor Dr. Gerhard Bohrmann of MARUM – Center for Marine Environmental Sciences and Department of Geosciences at the University of Bremen, now reports the discovery in a journal. Scientific reports.

Hydrothermal vents are seepages on the seafloor from which hot fluids escape. “The water penetrates the ocean floor, where it is heated by magma. The superheated water then rises through cracks and fissures back to the seafloor. On its way up, the fluid is enriched with minerals and materials dissolved from the rocks of the oceanic crust. Those fluids often re-percolate on the seafloor through conduits chimneys called black smokers, where metal-rich minerals then precipitate,” explains Professor Gerhard Bohrmann of MARUM and chief scientist of the MARIA S. MERIAN (MSM 109) expedition.

In a water depth greater than 3,000 meters, the remotely operated submersible vessel MARUM-QUEST took samples from the newly discovered hydrothermal field. Named after Jøtul, a giant in Norse mythology, the field is located on the 500 kilometer long Knipovich Ridge.

The ridge lies in the triangle formed by Greenland, Norway and Svalbard at the interface of the North American and European tectonic plates. This kind of plate boundary, where two plates are moving apart, is called a spreading ridge.

The Jøtul field is located on an extremely slow spreading ridge with plate growth rates of less than two centimeters per year. Because very little is known about hydrothermal activity on slow-spreading ridges, the expedition focused on obtaining an overview of escaping fluids as well as the size and composition of active and inactive smokers in the field.

“The Jøtul Field is a discovery of scientific interest not only because of its location in the ocean, but also because of its climatic significance, which was revealed, among other things, by our detection of very high concentrations of methane in fluid samples,” the report said. Gerhard Bohrmann.

Methane emissions from hydrothermal vents indicate a strong interaction of magma with sediments. As it travels through the water column, much of the methane is converted to carbon dioxide, which increases the concentration of CO₂ in the ocean and contributes to acidification, but also impacts climate when it interacts with the atmosphere.

The amount of methane from the Jøtul Field that eventually escapes directly into the atmosphere, where it then behaves as a greenhouse gas, still needs to be studied in more detail. Little is also known about organisms living chemosynthetically in the Jøtul Field. In the darkness of the deep ocean, where photosynthesis cannot take place, hydrothermal fluids form the basis for chemosynthesis, which is used by very specific organisms in symbiosis with bacteria.

In order to greatly expand the somewhat sparse information available on Jøtul Field, a new MARIA S. MERIAN expedition under the leadership of Gerhard Bohrmann will be launched at the end of this summer. The focus of the expedition is the exploration and collection of samples from the hitherto unknown areas of the Jøtul Field. With the extensive data from Jøtul Field, it will be possible to make comparisons with several already known hydrothermal fields in the Arctic Province, such as Aurora Field and Loki’s Castle.

The published study is part of the Bremen Cluster of Excellence “The Ocean Floor—Earth’s Uncharted Interface”, which investigates the complex processes on the sea floor and their impact on the global climate. The Jøtul field will also play an important role as an object of future research in the Cluster.