Water temperatures in the high Arctic hover just above freezing, while fifteen-foot seas are often choked with drifting ice, creating a formidable barrier that keeps most ships at bay. However, three summers ago, a dedicated research crew took on the challenge of these harsh conditions to uncover something that remains largely invisible from the surface: cracks in the seabed that release scalding fluids. Their perseverance led to a groundbreaking discovery—Jøtul, the first hydrothermal vent field ever recorded along a 311-mile stretch of the Knipovich Ridge between Greenland and Svalbard.
Since the initial discovery of hydrothermal vents near the Galápagos Islands in 1977, these natural phenomena have captivated scientists worldwide. Hydrothermal vents are formed when seawater plunges through fractured oceanic crust, encounters magma, and then returns to the surface enriched with metals and various chemicals, often at temperatures hot enough to melt lead. The Jøtul vent field adds a significant chapter to this narrative, located nearly 1.9 miles below sea level on one of Earth's slowest-spreading ridges, where tectonic plates drift apart at a rate of less than 0.8 inches per year.
What sets Jøtul apart is its position; rather than being located on the central ridge where magma typically rises to the crust, these vents are found off to the side. This unusual positioning suggests a unique geological process at play, hinting that many more Arctic vents remain undiscovered beneath the ice.
Most mid-ocean ridges are situated in temperate or tropical waters, leaving the Arctic's hydrothermal systems poorly mapped. While satellite altimetry has revealed that the ridge extends 2,485 miles across the ocean floor, the dense pack ice has severely limited sonar surveys and dive time for manned vessels. However, advancements in technology have transformed exploration efforts. In 2021, a drone-like autonomous vehicle detected unusual chemical spikes in water samples taken 1,000 feet above the seabed, indicating plumes from hydrothermal vents rich in hydrogen and manganese—signatures typically associated with these geological features.
The research team returned with the remotely operated vehicle MARUM-QUEST, successfully guiding it through the inky darkness to the source of these plumes. The cameras revealed stunning images of shimmering water filled with metallic flakes. The vent fluid, which reaches temperatures exceeding 600.8 °F, bursts forth from narrow chimneys known as "black smokers." Nearby, cooler and clearer jets flow from cracked pillow basalt, confirming the hypothesis that magma in this region travels sideways through faults before heating trapped seawater.
Traditionally, it was believed that hydrothermal vents thrive where fresh crust forms rapidly, leading to the assumption that slow ridges like Knipovich were nearly barren. However, evidence from other Arctic sites, such as Aurora and Loki’s Castle, has already revealed active venting despite limited magma supply. Jøtul reinforces this pattern, suggesting that slow geological processes may actually promote biodiversity. Some black smoker chimneys at Jøtul were tall and coated in sulfur, while others were toppled and dark, indicating a history of geological activity.
According to Prof. Gerhard Bohrmann of MARUM and chief scientist of the MARIA S. MERIAN (MSM 109) expedition, “Water penetrates into the ocean floor where it is heated by magma. The overheated water then rises back to the seafloor through cracks and fissures. On its way up, the fluid becomes enriched in minerals and materials dissolved from the oceanic crustal rocks.” The resulting fluid often escapes at the sea floor through chimneys, where metal-rich minerals precipitate, showcasing the complex interactions between geological and biological systems.
While hydrothermal vent fields typically emit hydrogen sulfide and iron, Jøtul introduces an intriguing twist: exceptionally high levels of methane. Prof. Bohrmann noted, “The Jøtul Field is of scientific significance not only because of its location but also due to its climate implications, revealed by our detection of very high concentrations of methane in the fluid samples.” Methane bubbles originating from depths of three miles often do not reach the atmosphere intact; instead, bacteria and oxidation convert much of the gas into carbon dioxide before it surfaces. Nonetheless, the deep plumes contribute to the global carbon cycle, making their tracking crucial for climate models that struggle with seafloor emissions.
Despite the absence of sunlight at such great depths in the Arctic, hydrothermal vent chimneys teem with life, including limpets and white polychaete worms. Nearby rocks are coated with bacterial mats resembling wet paper. These organisms do not rely on photosynthesis; instead, they utilize chemosynthesis—a process where microbes oxidize hydrogen sulfide or methane, and larger animals gain energy through grazing, filter feeding, or symbiosis. The communities around these vents have sparked theories suggesting that life’s earliest ancestors could have evolved in similar habitats billions of years ago.
Jøtul's unique chemistry and mineralogy challenge existing narratives about vent ecosystems, particularly because cooler seeps in this region allow for the formation of both carbonate and sulfide deposits. The extreme seasonal variations in surface productivity may also provide additional organic material for the resident fauna. Future research aims to compare the DNA of Jøtul’s inhabitants with samples from southern vents to investigate whether the isolation of polar ecosystems has led to the emergence of new species.
This summer, the MARIA S. MERIAN will return to the Knipovich Ridge equipped with upgraded sensors and a drill capable of coring living chimneys. Researchers seek to gather time-series data on plume height, fluid composition, and vent temperature. They will also conduct detailed mapping of the seafloor surrounding Jøtul to identify smaller seeps that may have been overlooked during the initial exploration. Results from this expedition will contribute to the Bremen-based project “The Ocean Floor – Earth’s Uncharted Interface,” which aims to link geology, biology, and climate science.
Each new hydrothermal vent field discovered shifts attention toward the vast unexplored regions of the global ridge system. Currently, only about one-fifth of the Earth's seafloor has been mapped at the necessary resolutions to locate vent chimneys. As autonomous vehicles become more robust and satellite communications improve, the Arctic—once considered an afterthought—may emerge as the next frontier for understanding the intricate relationships between oceans, rocks, and the atmosphere. Jøtul serves as a reminder that even in 2025, our planet still holds fiery secrets beneath the ice.
The full study detailing these findings was published in the journal Scientific Reports.
—– Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.
