The delicate oceanic depths are not exactly inviting for terrestrial creatures. In addition to the lack of light to see through and air to breathe, the weight of all the water above creates crushing pressure.
But this lightless part of the world teems with life of its own; life that has evolved to thrive in these conditions, life that looks very different from anything you might find on drier shores.
Much of this life, throughout much of human history, has been inaccessible. It’s down there, in the darkness, doing its thing. But the relatively recent invention of remotely operated underwater vehicles, or ROVs, is finally opening our eyes to this dark, strange, silent world.
In October 2019, scientists at the Schmidt Ocean Institute aboard the research vessel Falkor encountered such a creature while piloting the ROV SuBastian: an otherworldly squid, rarely seen by human eyes. This genus lives in the lower mesopelagic and bathypelagic depths of the ocean – up to 4,000 meters (13,123 feet) down, almost completely out of reach of the sun’s rays.
We briefly came across this beautiful squid yesterday during a #DesigningTheFuture ROV dive. Anyone have a name or more info about it? @MBARI_News @SarahMackAttack @TheOctoNation @BioinspirLab @KakaniKatija @universityofri @urigso @bphillipsdeep6 @wyssinstitute pic.twitter.com/h83lO5GyBd
— Schmidt Ocean (@SchmidtOcean) October 15, 2019
The Planctoteuthis captured in the rare images (now surfaced by the institute on the occasion of its two-year anniversary) looks very little like you would expect from a squid.
It has a long, graceful tail with many appendages; his arms, on the other hand, seem quite small. In this individual, the tail is adorned with long, blue streamers and cells called iridophores, which glitter as the squid shuffles through the water.
These iridophores are stacks of very thin cells that can reflect light at different wavelengths. Here they glisten in gold, reflecting the light from the ROV’s headlights. In the dim conditions under which the squid usually live, these cells can utilize the little light available to flicker and flash, although their purpose is unknown. It could be to attract prey, scare off predators, or communicate with other squid, or perhaps a combination.
This small, delicate genus of squid is largely known from samples taken from the deep and damaged in the process. We have only seen Planctoteuthis very rarely lives in its natural habitat, so there’s a lot we don’t know.
For example, scientists have found in the samples features that are usually only found in juvenile squid. This suggests that the genus could be neotenic, or mature slowly. We also don’t know the reason for the long, extended tails.
However, if a creature doesn’t look like its kind, there’s a good bet it looks like something else. This is called mimicry and in the animal kingdom it often provides an advantage in avoiding predators. this particular Planctoteuthis is believed to resemble a siphonophore, a composite animal that possesses stinging cells and flashes light to attract prey.
Planctoteuthis could hijack the appearance of a siphonophore to try to attract similar prey, as well as ward off the predators that would normally be wary of being stung by a siphonophore.
As we continue to dive deep into the ocean, we can only learn more about these mysterious squids. In 2014, Schmidt scientists caught a different species Planctoteuthis on camera, and last year scientists at the Monterey Bay Aquarium Research Institute also managed to capture a sighting.
Each expedition brings us rare sightings that tell us a little more about this eerie, beautiful and mysterious world.