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Sheltering his equipment in a self-made waterproof housing, Audun Rikardsen used his own system for adjusting the focus and aperture during a single exposure, as moon jellyfish swarmed in the cool autumnal waters of a fjord outside Tromsø, in northern Norway, illuminated by the aurora borealis.

She added moon jellyfish normally feed towards the top of the water surface, but when, as is currently the case, "waters are hotter than average" it can negatively impact its swimming ability.

"Luckily, moon jellyfish do not have a strong enough sting to harm humans - so if anyone falls off their paddleboard they'll be safe," she said.

The scientists captured high-speed video of eight moon jellyfish, Aurelia aurita, to investigate their swimming motion.

The moon jellyfish in the video above might seem like an odd candidate for the underwater Olympics.