A beautiful new wonderland has been discovered, hidden deep beneath the ocean waves of the Arctic Circle.
Off the coast of Svalbard, Norway, a field of hydrothermal vents unfolds more than 3,000 meters deep along the Knipovich Ridge, an underwater mountain range previously considered fairly inconspicuous.
Instead, like underfloor heating, the volcanic activity beneath the seabed causes heat to seep through, creating havens of heat and chemical reactions where life can gather and flourish.
The field, which is at least a kilometre long and 200 metres wide, has been named Jøtul, after the giants from Norse mythology who live under the mountains. In this case, the giant is the Earth’s internal processes, which are released through cracks in the seabed.
“Water penetrates to the bottom of the ocean, where it is heated by magma. The superheated water then rises back to the bottom of the sea through cracks and crevices,” explains marine geologist Gerhard Bohrmann of the University of Bremen in Germany .
“On its way up, the fluid is enriched with minerals and materials dissolved from the oceanic crustal rocks. These fluids often seep back down to the seafloor through tubular chimneys called black smokers, where metal-rich minerals are then precipitated.”
Hydrothermal vent fields are among the most interesting submarine environments. They are usually found very deep below the ocean’s surface, so deep that light from the sun cannot penetrate the vast amount of water above.
At these depths, conditions are permanently dark, icy and surrounded by crushing pressure.
This environment is not exactly conducive to life, but hydrothermal vents act as strange oases. The minerals that seep out and dissolve in the water form the basis for a food web that depends not on photosynthesis, like most life closer to the surface, but on chemosynthesis – the harnessing of chemical reactions for energy, rather than sunlight.
This environment makes for a much more dynamic and thriving deep-sea floor than you might expect, giving us a glimpse into how life might emerge on worlds very different from our own.
Finding hydrothermal fields is also important for protecting Earth’s biodiversity, learning more about how it functions, and understanding how the planet itself functions and changes over time.
The Jøtul field lies right on the boundary between two tectonic plates of the Earth, on what is known as a slowly spreading ridge. The plates move away from each other very slowly, stretching the crust and creating valleys and ridges.
Scientists have detected hydrothermal activity along almost all mountain ridges north of Iceland, but the Knipovich Ridge remained a glaring exception.
That was until 2022. Scientists had seen hints of hydrothermal chemistry in the region, so they took a remote-controlled underwater vehicle to the ridge to see if they could find its source.
They drove the MARUM QUEST submerged more than 3 kilometers to the seafloor, where it took images and collected water samples. And there they found the Jøtul field – a large area on the seafloor of both extinct and active hydrothermal vents, and the treacherous glare of volcanic heat seeping into the water.
It is an amazing find, filling an important and previously puzzling gap in the hydrothermal structure of the Norwegian-Greenland Sea.
“The Jøtul hydrothermal field is the first discovered along the 500-kilometer-long, ultra-slow spreading Knipovich Ridge and is important because it represents a new link between the active hydrothermal systems of Loki’s Castle in the Bight of Mohns and Knipovich Ridges and the Aurora hydrothermal field of the Gakkel Ridge,” the researchers write in their paper.
“Since these systems are more than 1,000 kilometers apart, the discovery of the Jøtul hydrothermal field is important for understanding the distribution of chemosynthetic faunal communities.”
In addition, the new discovery could provide insights into the chemistry of the ocean and how the water that makes up our world contributes to the circulation and distribution of materials such as carbon.
The research was published in Scientific reports.