The iconic ‘Dumbo’ octopus stars in the deepest-ever octopus sighting

The adorable cephalopod has been photographed on the bottom of the Indian Ocean in the Java Trench, at around 7,000 meters of depth.

Image credits amieson, A.J., Vecchione, (2020), Mar Biol.

This is roughly 2 kilometres deeper than any previous reliable sighting of a cephalopod, the family that includes octopus and squids. Given that we now know how deep these animals can live — seemingly very comfortably, too — the findings “increase the potential benthic (ocean floor) habitat available to cephalopods from 75 to 99% of the global seafloor”.

The deep end

The researchers who spotted the boneless animal say it’s a species of “Dumbo” octopus, so named due to its distinctive side fins. Due to their size and shape, they’re very reminiscent of an elephant’s ears, most notably to those of Disney’s 1940s’ animated elephant Dumbo.

Still, spotting the octopus at this depth was no mean feat. Lead author Dr Alan Jamieson from the School of Natural and Environmental Sciences, Newcastle University is a pioneer of the use of “landers” for deep-sea exploration. These landers are crew-less craft, in essence large metal frames outfitted with various instruments that are dropped overboard and land on the seafloor. Once there, they observe their surroundings and record any passers-by.

And record they did. The lander picked up two octopuses, a 43-cm-long one at a depth of 5,760m and the other (35 cm) at 6,957m. Based on their physionomy, Dr. Jamieson and his co-author Michael Vecchione from the NOAA National Systematics Laboratory are confident that they belong to the Grimpoteuthis family, the group commonly known as the Dumbo octopuses.

God, it’s so cute.
Image credits amieson, A.J., Vecchione, (2020), Mar Biol.

Further down, the landers also spotted octopus fragments and eggs. The study provides the deepest-ever sightings of cephalopods. Previously, the deepest reliable sighting was a 50-year-old black-and-white photograph of one such animal taken at a depth of 5,145m.

For starters, it’s impressive that anything can live at such depths, where pressure is literally crushing.

“They’d have to do something clever inside their cells. If you imagine a cell is like a balloon — it’s going to want to collapse under pressure. So, it will need some smart biochemistry to make sure it retains that sphere,” Dr. Jamieson explained.

“All the adaptations you need to live at pressure are at the cellular level.”

Furthermore, it helps fill out our understanding of hoe octopuses live. The authors explain that the study shows that such animals can (potentially) live across 99% of the global seafloor, as the Java Trench is one of the deepest points on Earth.

The paper “First in situ observation of Cephalopoda at hadal depths (Octopoda: Opisthoteuthidae: Grimpoteuthis sp.)” has been published in the journal Marine Biology.

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