NOAA

The expedition has only just begun and already it is producing some stunning footage of the denizens of Earth’s deepest abyss.

NOAA’s Okeanos research ship will spend the next two months cruising the seas above the Mariana trench, using sonar systems and a remotely operated vehicle (ROV) to explore the little known parts of the trench and its surroundings.

Footage from the daily dives is being live-streamed, with highlights posted on the expedition site. On 24 April the ROV captured this footage of a beautiful jellyfish (see video above), belonging to the Crossota genus, at a depth of nearly 4 kilometres.


On 25 April it filmed a striking, violet sea cucumber swimming above the sea floor (see video below).

The trench is famous for being the deepest in the world, but the ROV will not be going 11 kilometres down to the very bottom, as James Cameron did in 2012. It can only reach down to 6 km.

For now researchers cannot explore any deeper: Cameron’s submarine was not designed for long-term use and the one semi-autonomous vehicle that could go deeper imploded in the Kermadec trench in 2014 at a depth of 10 km. But a new deep-sea exploration vehicle should be ready soon.

Going so far down isn’t just a challenge for us. There is a limit to how deep fish and some other animals can go too (see The deepest limits: How low can fish go?).

The cameras also snapped pricklefish at nearly 5 km, as well as various bits of rubbish, including a beer can at 3780 metres.

Earlier this year, NOAA led an expedition to the waters of the Papahanaumokuakea Marine National Monument of north-west Hawaii, where it also revealed new life forms, including a ghostly octopus filmed 4290 metres under the surface.