What's at the Very Bottom of the Mariana Trench?

A Texas businessman has broken world records by plumbing the depths of the world’s deepest known location, the Challenger Deep at the Mariana Trench. In his submarine DSV Limiting Factor, Victor Vescovo descended to a staggering 10,927m below sea, breaking the record previously held by filmmaker James Cameron. DSV Limiting Factor also became the first vessel to visit the Mariana Trench on more than one occasion.

The expedition forms part of the Five Deeps Expedition, a year-long journey into the deepest parts of all five of the world’s oceans, and has uncovered some interesting new discoveries. Three new species of marine organisms were discovered during the five dives, including a crustacean known as an amphipod. Unfortunately, the team also found evidence of a plastic bag and sweet wrappers, which serves to highlight the seemingly ubiquitous danger of microplastic pollution in today’s world.

Breaking records

Oceanic exploration has evolved significantly over the last 60 years. In comparison to the first submersible which visited the Challenger Deep in 1960, Vescovo’s vessel is unrecognisable. The submarine employs 90mm-thick titanium in its hull, specifically designed to withstand the intense pressures of the deep sea, and is capable of reaching an incredible 11,000m below sea level.

On this particular occasion, the DSV Limiting Factor reached a depth of 10,927m, which is 19m deeper than the record set by the director of Titanic in 2012. It also became the first sub to revisit the site on multiple occasions, returning for five dives in a space of eight days. Each descent takes approximately three-and-a-half hours, followed by a four-hour exploration session and a three-and-a-half hour ascent back to the surface.

“It is almost indescribable how excited all of us are about achieving what we just did,” explained Vescovo. “This submarine and its mother ship, along with its extraordinarily talented expedition team, took marine technology to an unprecedented new level by diving - rapidly and repeatedly - into the deepest, harshest area of the ocean. We feel like we have just created, validated, and opened a powerful door to discover and visit any place, any time, in the ocean - which is 90% unexplored.”

Inspiring and alarming discoveries

Equipped with hi-tech cameras and sophisticated equipment aimed at monitoring efficiency and gathering information about the ship’s surroundings, the DSV Limiting Factor was able to collect important samples from the Challenger Deep. Among these were several as yet undiscovered forms of marine life, including a type of crustacean that loosely resembles a shrimp.

However, it was the submarine’s other discoveries which caused concern. Their cameras detected something which the team believe to be a manmade object and most likely a plastic bag, although they stress that they are unable to definitively confirm what it is. In any case, it is ambitious exploration projects like this one which will better equip us with the understanding of the extent of the problem. Similarly advanced technological solutions (such as the unlikely combination of artificial intelligence and forensic science) will then be needed to provide the answer.

As for Vescovo, he and his submarine are heading next to Horizon Deep at Tonga Trench, which is the second deepest in the world and the deepest in the southern hemisphere. Then it’s onto the Molloy Deep in the Arctic Ocean, completing the Five Deeps Expedition in full.