Deep-sea ‘piglet’ squid, Helicocranchia sp., probably an undescribed species. Photo: Kat Bolstad
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When you picture where creatures live on Earth, what do you see?
A tropical jungle? A highland pasture? An inland lake? Maybe a rocky seashore?
All of it combined – ecosystems on land, plus shallow coasts – makes up just 5% of the liveable space on our planet.
Instead, maybe you should be picturing somewhere dark, cold, and under hundreds of metres of water.
The deep-sea world
“If aliens would come to planet Earth and sample the habitats here to find out what our biodiversity is like, they could conceivably have to sample 95 times before they would find a habitat that was not deep sea,” says Associate Professor Kat Bolstad from Auckland University of Technology.
This is why scientists are still finding new species of deep-sea squid.
Kat Bolstad holding a deep-sea ‘bottletail squid’ (Sepioloidea virgilioi). Photo: Rebekah Parsons-King / NIWA
When Kat says deep-sea, she means the part of the ocean below the sunlight (“photic”) zone, where photosynthesis can take place. But even without sunlight, there are plenty of creatures down there making their own light though bioluminescence.
It’s a very different world to our up-top, dry-air, UV-intense spaces, which makes it tricky for us to visit and study. You can lower submarines or equipment down there. But squid are alert to anything strange in their environment and tend to make themselves scarce.
Kat does make use of such exploration methods and has even been down to depths of 1,000 metres in a bubble submarine in the Antarctic herself. But to unravel the secret lives of squid, she also relies on other avenues. Like “squid Christmas”.
‘It’s the most wonderful time of the year’
Kat Bolstad with a giant squid tentacle. Photo: Sadie Mills / NIWA
Every year, Kat and some of her research team travel to Wellington for “squid Christmas” – a clean out of NIWA’s freezers that sometimes yields “presents” in the form of ”squidsicles” – frozen squid specimens.
It’s always a time of excitement.
“Anytime you look at samples from the deep sea, there’s a reasonable chance that you will see something that no human has ever seen before,” says Kat.
As well as NIWA, Kat collaborates closely with Te Papa and Auckland Museum, who also have marine collections filled with deep-sea treasures collected by research vessels on fishing surveys, biodiversity sampling, or discovery expeditions.
Focusing on squid eyes
An array of glass jars filled with amber liquid sit on a lab bench. Inside them: small whole squid, bent at strange angles, and grape-sized squid eyes in little plastic bags. One eye is the size of your palm.
These specimens are part of PhD candidate Ryan Howard’s research. In the adjoining room, Ryan points out the largest sample he has: a giant squid eye in a bucket of formalin. He dissected it out of a giant squid himself.
Deep-sea ‘strawberry’ squid (Histioteuthis heteropsis). Photo: Kat Bolstad
Ryan has all these eyes because he’s interested in how squid see the world. He’s decided to focus on 12 species, including the commercially important arrow squid and the intriguing strawberry (or cock-eyed) squid. The latter have eyes of two very different sizes: one thought to keep an eye on things moving overhead backlit by sunlight, the other to spot bioluminescent light down in the dark.
For the research, Ryan will investigate the morphology of the eyes – their shape and structure, but also the photopigments. These are the molecules within the light receptors in eyes that determine how good the squid is at seeing intensity and colours of different light. He also plans to take MRI images of squid brains, to investigate their optic lobes – the part responsible for sight.
PhD candidate Ryan Howard with a squid eye. Photo: Claire Concannon / RNZ
Overall, he’s hoping to get a better picture of the diversity of eye structure in squid, and how they use different approaches to navigate their dark worlds.
Listen to the episode to learn more about how Kat and her team go about researching squid, what their world is like, and why, if they had the capacity to do so, they might view us as monsters.
Learn more
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Listen to this 2014 episode, which includes Dr Kat Bolstad talking about the examination of the colossal squid that is now on display in Te Papa.
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To learn more about bioluminescence in the ocean, listen to Glow in the dark.
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Squid are a favourite snack of albatross, but unfortunately this means that they frequently interact with the deep-sea squid fishery, often to their detriment.
