National Oceanic and Atmospheric Administration

While the public has been waiting for film director James Cameron to produce a sequel to his blockbuster Avatar, oceanographers have been wondering when he would release the science results of his dive to the bottom of the ocean last March. On Tuesday, Cameron and his team doled out a few tidbits to a packed audience at a meeting of the American Geophysical Union in San Francisco.

“We did end up with some amazing science results from this project,” says Cameron.

On 26 March, he piloted his newly finished submersible, the Deepsea Challenger, to the floor of the Mariana Trench and became the first human since 1960 to reach the lowest spot in the ocean—at a depth of 10,900 metres. In trials before that, he set the record for currently operating submersibles by diving down to 8,200 metres to the bottom of the New Britain Trench, which had never been explored by humans or by remotely operated vehicles in the past. “It was basically terra incognita from a science perspective,” says Cameron.

In terms of biology, the New Britain Trench looked like New York City compared to the desert at the bottom of the Mariana Trench. On dives with the submersible and with robotic vehicles, the team found thriving communities of acorn worms and sea anemones at the bottom of the New Britain trench, which were fed by nutrients coming from nearby islands. “There was a lot of nutrient input,” says Douglas Bartlett, a microbiologist at the Scripps Institution of Oceanography in La Jolla, California. “It was incredible to see logs at 8.2 kilometres.”

Cameron had hoped to do more dives in the Mariana trench but ran out of time, in part because of a helicopter accident that killed two crew members earlier in the expedition, he says. Aside from Cameron’s single trip to the bottom, the submersible went down in an unmanned check-out dive and the robotic vehicles visited two spots on the seafloor in the trench. One of those sites was in a basin called the Serena Deep.

“What was very exciting about the Serena Deep dive was we could see outcrops and bizarre microbial mats covering the rocks,” says Kevin Hand, an astrobiologist at the Jet Propulsion Laboratory in Pasadena, California. The researchers suspect that the outcrops contain rocks from the mantle that are being altered by a process called serpentinization, in which sea water reacts with minerals and releases hydrogen and methane. Those could provide the energy to feed the microbial communities seen at the site, says Hand.

The findings have implications for the origins of life on Earth and other planets, he says. Researchers have speculated that the process of serpentinization in the early oceans could have supplied the energy and raw materials critical for a primordial metabolism, which could eventually have given rise to the first cells. “Serpentenization is seen to be a possible culprit in that step between geochemisty and biochemistry,” says Hand.

Cameron doesn’t have concrete plans to take his sub for a spin anytime soon, but he says he hopes to gain funding for future missions and will make the technology available to the scientific community. In the meantime, he may get involved in a Mars mission.

Cameron helped develop a stereo zoom camera system for the Mars Curiosity rover, but NASA took those advanced cameras off the craft shortly before launch and replaced them with simpler imagers. NASA announced on Tuesday that it will send a mission to Mars in 2020 using some of the technology developed for Curiosity. Hearing that at the meeting, Cameron said, “I’ll immediately go and start banging the drum to get the zoom version flown.”