Some 6.2 miles below the surface of the Pacific, tragedy very likely struck. What the BBC describes as one of the "most capable deep-sea research subs" in existence has vanished—and likely imploded. The $8 million Nereus was in the Kermadec Trench northeast of New Zealand, among the world's deepest spots, when it went missing on Saturday afternoon. Debris found at the surface indicates that at least part of the hybrid remotely operated vehicle likely imploded under pressure as great as 16,000 pounds per square inch.
A press release from the Cape Cod-based Woods Hole Oceanographic Institution that built and operated the vehicle explains that researchers aboard the Thomas G. Thompson lost contact with the Nereus during a planned nine-hour dive of the deepest extent of the trench. The debris spotted by the ship will be analyzed to verify its source and to attempt to find clues in the Nereus' demise. Among the standout details of the vehicle, which was built in 2008: It is one of just four submersibles to ever reach the deepest part of the ocean in the Mariana Trench; it has collected specimens of animals previously unknown to science; and it explored the world's deepest known hydrothermal vents along the Caribbean's Cayman Rise. The Cape Cod Times notes it's not the first loss WHOI has suffered: Nereus predecessor ABE vanished—without a trace—off the coast of Chile in March 2010.