Around the world, hydrothermal vents are located at the intersections of shifting tectonic plates, with numerous hydrothermal fields yet to be uncovered. The first hydrothermal vent field on the 500-kilometer-long Knipovich Ridge off the coast of Svalbard was found during a 2022 expedition of the MARIA S. MERIAN.
Prof. Dr. Gerhard Bohrmann of MARUM – Center for Marine Environmental Sciences and the Geosciences department at the University of Bremen led an international team of researchers from Bremen and Norway to report on the discovery in the professional journal Scientific Reports. These vents on the sea floor are outlets from which hot liquids are released.
“Water penetrates into the ocean floor where it is heated by magma. The overheated water then rises back to the sea floor through cracks and fissures. On its way up, the fluid becomes enriched in minerals and materials dissolved out of the oceanic crustal rocks. These fluids often seep out again at the sea floor through tube-like chimneys called black smokers, where metal-rich minerals are then precipitated,” explains Prof. Gerhard Bohrmann of MARUM and chief scientist of the MARIA S. MERIAN (MSM 109) expedition.
The MARUM-QUEST, a remotely controlled submersible vehicle, collected samples from a hydrothermal field recently discovered at water depths exceeding 3,000 meters. Named after Jøtul, a figure in Nordic mythology, the field is situated on the Knipovich Ridge, which spans 500 kilometers. This ridge is positioned within the triangle formed by Greenland, Norway, and Svalbard at the junction of the North American and European tectonic plates. Such a plate boundary, where two plates move apart, is referred to as a spreading ridge.
The Jøtul Field is located on an exceedingly slow-spreading ridge, with the plates growing at a rate of less than two centimeters per year. Due to the limited knowledge of hydrothermal activity on slow-spreading ridges, the expedition’s primary focus was to gain an understanding of the released fluids and the size and composition of both active and inactive smokers in the area.
“The Jøtul Field is a discovery of scientific interest not only because of its location in the ocean but also due to its climate significance, which was revealed by our detection of very high concentrations of methane in the fluid samples, among other things,” reports Gerhard Bohrmann.
The presence of methane emissions from hydrothermal vents suggests an energetic interaction between magma and sediments. As the methane travels through the water column, a significant portion of it is transformed into carbon dioxide, increasing oceanic CO2 levels and contributing to acidification.
Additionally, the interaction of methane with the atmosphere also impacts climate. Further research is necessary to thoroughly examine the quantity of methane from the Jøtul Field that escapes directly into the atmosphere, where it subsequently functions as a greenhouse gas.
The Jøtul Field is home to organisms that live through chemosynthesis, a process based on hydrothermal fluids in the deep ocean where photosynthesis cannot take place. These specific organisms form symbiotic relationships with bacteria to carry out chemosynthesis.
To gather more information about the Jøtul Field, an upcoming expedition of the MARIA S. MERIAN will be led by Gerhard Bohrmann. Scheduled to commence in late summer, the main objective of the expedition is to explore and collect samples from previously unexplored areas within the Jøtul Field.
The abundant data obtained from the Jøtul Field will allow for comparisons to be made with the few existing hydrothermal fields in the Arctic region, such as the Aurora Field and Loki’s Castle. Additionally, the Jøtul Field will be vital for future research in the Cluster.
Journal reference:
- Gerhard Bohrmann, Katharina Streuff, Miriam Römer, Stig-Morten Knutsen, Daniel Smrzka, Jan Kleint, Aaron Röhler, Thomas Pape, Nils Rune Sandstå, Charlotte Kleint, Christian Hansen, Christian dos Santos Ferreira, Maren Walter, Gustavo Macedo de Paula Santos & Wolfgang Bach. Discovery of the first hydrothermal field along the 500-km-long Knipovich Ridge offshore Svalbard (the Jøtul field). Scientific Reports, 2024; DOI: 10.1038/s41598-024-60802-3