According to biologist Jeff Drazen, there was a moment when the camera feeds from five miles below the Pacific revealed an image that no one on board had anticipated seeing. Drazen described this moment with a kind of quiet disbelief. A pale, nearly transparent fish with a scalloped face, wide fins spread out like wings, and a tail that tapered like an eel was floating through complete darkness as though it had been there forever. The group gazed at the screen. It was dubbed the “ghost fish.” The name stuck.
The Mariana Trench, a 1,500-mile hole in the Pacific floor close to Guam, has long held a peculiar place in the minds of scientists. Intellectually, people are aware that it is the deepest location on Earth. Down seven miles. perpetual gloom. cold that doesn’t change. pressure that, in a split second, would completely destroy a human body. For a long time, it was believed that only the most basic, barely surviving forms of life could be supported by something so harsh. The findings of the expedition on the research ship Falkor indicated that assumption was seriously incorrect.
The team used landers that resembled big refrigerators and were loaded with instruments and cameras. They descended using air-filled, thick glass spheres that had to withstand pressures high enough to crush nearly everything else on the planet. During the expedition, one of the spheres cracked and imploded in a microsecond, creating a detonation-like shock wave that rippled through the trench. It was recorded by the microphone. The sound reverberated for a disturbingly long time in those chilly, silent depths. The lander itself made it out alive. However, it’s the kind of detail that makes you truly understand the struggles these machines endure.
The cameras waited once they were on the bottom. And the supposedly empty trench came to light. The traps attracted swarms of amphipods, shrimp-like creatures that moved through the dark in hordes, eating whatever bait the fish left behind, beyond the ghost fish, which is now thought to be a new species of snailfish that lives deeper than any fish had previously been recorded. Living specimens of another novel species of snailfish were actually caught in separate traps. The animals were brought to the surface only to be destroyed by the decompression on the way back up, which seems like a tragedy in and of itself.
Trimethylamine oxide, a chemical that keeps cell membranes flexible rather than rigid under extreme pressure, is what makes the ghost fish and its neighbors physically possible. It serves as a reminder that biology has been solving engineering problems for far longer than engineers have, and it is a silent, molecular solution to a problem that would otherwise prevent life at those depths.
The findings about microbes might be even more bizarre. Scientists discovered green, fuzzy mats clinging to rocky outcrops in the Sirena Deep section of the trench. These communities of microbes appear to feed on chemicals produced by seafloor rocks reacting with water rather than organic material drifting down from above. Put another way, chemosynthesis. Geology is the only source of life. According to NASA astrobiologist Kevin Hand, these mats could serve as a guide for what might be living in the subterranean oceans of moons orbiting gas giants billions of miles away, such as Europa or Enceladus. According to filmmaker James Cameron, who co-led the DEEPSEA CHALLENGE expedition, it might be a window into the early stages of life on Earth four billion years ago.
Mengran Du, a geochemist, decided to survey one more section of the hadal trenches between Russia and Alaska with thirty minutes remaining in her submersible. The last thirty minutes resulted in the discovery of what her team believes to be the deepest known methane-based ecosystem on Earth: clams gathered in the dark, tube worms with red tentacles, and bacteria that transform hydrogen sulfide and methane into useful energy. Sunlight is not necessary. It had been there all along, spanning about 1,550 miles of seafloor.
Reading these results gives me the impression that the ocean’s deepest regions will continue to surprise us in ways that are truly difficult to predict. One of the team biologists, Paul Yancey, put it bluntly: there is a lot more life down there than people realized. There are people in the trench. It is still alive. To use Drazen’s term, it’s cooking—biologically complex, metabolically active, and seemingly content to be seven miles from the sun.
