Jules Verne would have dreamed of it! A Chinese submersible has discovered worms and mollusks living nearly 10,000 meters under the sea—the deepest-living colonies of organisms ever observed. This discovery suggests that other forms of life might thrive under the extreme conditions of the deep ocean, still largely unexplored on our planet, according to a team of Chinese scientists in an article published Wednesday in Nature.
Most life forms on Earth depend on sunlight, which is essential for photosynthesis. But in the pitch-black darkness of the deep ocean, some living beings survive thanks to chemicals like methane escaping from cracks in the ocean floor—a process scientists call chemosynthesis.
Last year, the Chinese submersible Fendouzhe (“The Striver”) dove 23 times into the Mariana Trench in the western Pacific Ocean, carrying researchers on board, according to the Nature study. There, they discovered colonies of thousands of tubeworms (whose bodies are encased in tubes) and bivalve mollusks at depths ranging from 2,500 to 9,533 meters.
A video released with the study shows vast fields covered with worms, up to 30 cm long, along with clusters of mollusks and clams.
Spiny crustaceans, free-floating marine worms, sea cucumbers, crinoids (feather stars), and other animals were also observed. These are “the deepest and most extensive chemosynthesis-based communities known on Earth to date,” the study emphasizes. Given that other ocean trenches have similar characteristics, such communities “might be more widespread than previously thought,” the authors suggest.
They also say they found “compelling evidence” of methane production by microbes, as tubeworms tend to cluster around microbial mats resembling snow.
Massive Pressure
The study’s publication comes as the controversial issue of deep-sea mining is debated at the international level. Both China and the United States have expressed interest in extracting valuable minerals from the deep sea. Oceanographers warn that mining the largely unexplored seafloor—one of the planet’s last wild frontiers—could wipe out fragile and poorly understood ecosystems.
Despite recent talks, the International Seabed Authority (ISA), which oversees mining in international waters, has yet to adopt binding regulations for the industry.
Chinese media have already reported that the Fendouzhe mission also aimed to conduct research on “deep-sea materials.” Only a handful of people have ever visited the bottom of the Mariana Trench, the deepest underwater valley on Earth. The first explorers reached it—a crescent-shaped depression deeper than the height of Mount Everest—in 1960.
No further missions were conducted until American filmmaker James Cameron’s solo descent in 2012—a world first. The Abyss director described the landscape as “alien” and “desolate.” At the bottom of the trench, the pressure reaches more than a ton per square centimeter—nearly 1,100 times the pressure at sea level.
