A two-week marine biology expedition off the coast of Brazil has uncovered 31 species new to science, a haul researchers say may set a record for the speed of deep-sea discovery.
Working in international waters of the South Atlantic aboard the research vessel Falkor (too), two dozen scientists from the United States, Australia, Brazil and Japan sampled the ocean midwater — the vast layer between the sunlit surface and the seafloor. The midwater encompasses roughly 90% of the planet''s living space, yet remains one of the least explored habitats on Earth. The expedition was operated by the Schmidt Ocean Institute with support from the University of Western Australia.
The catalogue of new species reads like a roll-call from a fantasy bestiary: a crustacean amphipod, a fast-moving gossamer worm, nine jellyfish, seven siphonophores (colonial relatives of jellyfish and coral), seven comb jellies famous for the glittering cilia they use to swim, four tadpole-like larvaceans that live inside houses of mucus, and two giant rhizarians — single-celled organisms big enough to see with the naked eye.
"It was pretty exciting," said chief scientist Dr Karen Osborn of the Smithsonian National Museum of Natural History. "The midwater is chock full of incredible animals that we don''t know much about. And this was an area that hadn''t been explored before so there were more opportunities to find new species. This must be close to a record for discoveries of new animals in a short space of time."
A new lens on the deep
What made the pace possible, the team says, was a piece of equipment they nicknamed the Squid — a spinning-wheel confocal microscope that uses lasers to scan the three-dimensional cellular structure of living organisms. It was the first time such an instrument had been operated on a working research vessel, allowing scientists to study delicate creatures while they were still alive instead of waiting until samples reached a shore-based lab.
"We could see cells interacting with each other, exchanging information in real time," Osborn said. The fragile, gelatinous animals that dominate the midwater often dissolve before they can be preserved, making in-situ imaging a long-standing dream for marine biologists.
The expedition also relied on SuBastian, the Schmidt Ocean Institute''s remotely operated submersible, to film and gently collect specimens from depths approaching 800 metres. One of the highlights was footage of a rarely seen female octopus consuming a jellyfish — a behavioural observation as scientifically valuable as the new species themselves.
Why it matters
Cataloguing the midwater is more than a curiosity project. The species that drift between the surface and the deep play outsized roles in the ocean''s biological pump, the daily migration of life that moves carbon from sunlit waters into the deep sea. Without knowing what lives there, it is hard to model how a changing climate, deep-sea mining proposals or shifting fisheries might ripple through the rest of the ocean.
"The midwater is the planet''s biggest habitat, and it''s still mostly unknown," said one of the expedition scientists. "Every dive turns up something we''ve never seen before."
Formal descriptions of the new species will be published over the coming months in peer-reviewed journals, where each will receive a Latin name and a place in the ever-expanding tree of life. For now, the team is calling the trip a reminder that, even in 2026, the ocean is still very good at keeping secrets — and even better at sharing them with anyone patient enough to look.
