Submitted by L.V.Audenhaege on
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Deep-sea abyssal plains form one of the largest biomes on Earth, covering more than 50% of the Globe. They constitute vast areas of the deep seabed (-3,500 to -6,000 m), where the darkness and the coldness (~2°C) reigns over. Still, a myriad of organisms has been observed there, relying on particles sedimenting from the surface as a food source. Those animals have often developed alien-looking adaptations to survive there, straight out from a science fiction movie. To have those observations during the SMARTEX cruise, we make use of the remotely operated vehicle Isis and the autonomous vehicle Autosub5. While Isis is very good at collecting animals with its robotic arms, Autosub5 can autonomously image the seabed over large distances (100 km). Both harbor cameras allowing us to encounter and observe fancy creatures. From these images, we derive ecological knowledge. For instance, we try to assess the composition of the biological community living on the seafloor, by counting and identifying each organism observed each in image. From there, we can assess if some species prefer particular areas in relation to environmental conditions, and even measure the biodiversity of the abyssal plain (i.e., number of species).

Can you take part in this exciting exploration survey by finding a fancy sea cucumber (Amperima sp. of 15 cm) in this 3D reconstruction of the seabed: Use the two mousepads to drag yourself along the image transect. Sea cucumbers spend their life wandering on seabed covered by sediment that they ingest to eat. If it was too easy, try counting the number of brittle stars. Enjoy the dive!

Extra quest. If you are brave enough, can you help to find a spooky lizardfish (Bathysaurus sp.), one of the biggest fish predators in the area: This one is approximately 80 cm long. It is waiting patiently to catch a prey wandering too close its mouth.


An Amperima sea cucumber wandering on an abyssal plain of the Pacific Ocean (-4000 m). This is a typical image of the seabed viewed from above, used to conduct ecological surveys in abyssal plains. Note the spread between the two red lasers, scaling 10 centimeters. (C) SMARTEX, NOC
An Amperima sea cucumber captured at ~4000 m, grazing on sediment covering the seafloor of the Pacific Ocean. This downward-looking image is one example of the many images (typically thousands) we usually annotate to gain ecological knowledge on deep-sea abyssal plain communities. Note the presence of a brittle star. The two red dots indicate 10 cm. (C) SMARTEX, National Oceanography Centre