A 35-day research expedition to the mid-Atlantic Ocean has returned with discoveries that scientists say ‘fundamentally expand our understanding of one of the planet’s most geologically active and least explored systems’. 

Findings from the expedition include two new hydrothermal vent fields, the first footage of a living barreleye fish species, and evidence that suggests heat-driven fluid circulation in the deep ocean may be far more widespread than previously recognised.

The expedition, conducted aboard Schmidt Ocean Institute’s research vessel Falkor (too), targeted the Doldrums Megatransform and Fracture Zone – a large, tectonically active system cutting across the Mid-Atlantic Ridge approximately 800 miles off the north-east coast of Brazil, just north of the equator. 

While hydrothermal vents have been documented along the Mid-Atlantic Ridge before, none had previously been found within the Doldrums system itself.

“This discovery shows why exploration still matters,” said Dr Aaron Micallef, senior scientist at the Monterey Bay Aquarium Research Institute and the expedition’s Chief Scientist. “Even in the Atlantic Ocean, where plate boundaries have been studied for decades, there are still places where the first close look can reveal something entirely new. This expedition showed that even in one of the most remote corners of the ocean, our planet remains alive, dynamic, and full of surprises.”

The first and larger of the two vent fields is extensive by any measure – covering approximately 99,000 square metres, roughly equivalent to 14 FIFA-standard football pitches. It comprises 23 individual hydrothermal vents, 13 of which feature active black smoker chimneys. The expedition team sampled superheated fluids reaching 280°C at the site, and observed anemones, crabs, and thousands of blind Rimicaris shrimp clustered around the vents – animals that sustain themselves not through photosynthesis but through chemosynthetic bacteria, which draw energy directly from the chemical compounds in vent fluid. 

A second, significantly smaller vent field was discovered 170 kilometres away during the expedition’s final remotely operated vehicle dive.

Initial observations suggest each vent field combines conventional volcanic venting with a chemical process known as serpentinization – a chemical reaction that occurs when rocks from the Earth’s mantle are exposed to seawater, producing heat and chemical energy without any requirement for sunlight. Only a small number of mixed vent fields with both volcanic and serpentinization-related characteristics have been identified worldwide. 

The Lost City hydrothermal field on the Mid-Atlantic Ridge is the most well-known example. The Doldrums system has now yielded two more.

“Serpentinization is a process in which seawater reacts with minerals in rocks, producing heat and chemical energy that allow life to thrive in the deep ocean without sunlight,” said Schmidt Ocean Institute Executive Director Dr Jyotika Virmani. “A better understanding of these systems could provide clues for finding life on other planets.”

The speed of the discoveries was made possible in part by a new tool making its scientific debut on this expedition. Schmidt Ocean Institute’s autonomous underwater vehicle, The Childlike Empress, was deployed for the first time on a scientific mission, generating high-resolution seafloor maps that allowed the team to pinpoint the first vent field’s exact coordinates and direct ROV SuBastian to the site with unusual efficiency.

The Childlike Empress mapped approximately 147 square kilometres of seafloor at one-metre resolution during the mission.

On one dive, the team observed two bigfin squids – Magnapinna sp. – at a depth of approximately 3,634 metres. The deepest-dwelling squid known to science, bigfin squids are characterised by thread-like tentacles that can reach eight metres in length and are rarely observed alive in their natural environment.

 The expedition also captured the first footage ever recorded of a living Winteria telescopa – a species of barreleye fish, filmed at 710 metres depth. Barreleye fish are notable for their translucent heads and tubular eyes oriented to detect the faintest traces of bioluminescence and dim light from above. 

Most existing knowledge of the species has been derived from net-caught specimens, typically damaged beyond detailed study by the time they reach the surface.

“We arrived searching for vents, faults, and seamounts. We leave with something even more valuable: a deeper understanding of ecosystems in one of the least explored regions of the Atlantic Ocean,” said Dr Paula Zapata Ramirez, assistant professor at the Universidad Pontificia Bolivariana. “Every sample, every image, and every discovery brings us one step closer to understanding the hidden parts of our planet.”

The expedition is one of several Schmidt Ocean Institute has undertaken in international waters since the passage of the United Nations Biodiversity Beyond National Jurisdiction Agreement in January 2026 – a framework designed to extend protections to the high seas, the vast stretches of ocean that lie beyond any single nation’s jurisdiction. The Doldrums Megatransform and Fracture Zone sits squarely in that category.

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