A robot jellyfish which mimics the movement of sea creatures has been invented by UK scientists in bid to more easily explore coral reefs.
Scientists at the University of Southampton and University of Edinburgh have developed the soft-shell robot, which uses a similar motion to squid and jellyfish, to allow access to delicate areas like shipwrecks and coral reefs which could be damaged by harder propeller-powered robots.
The robot is powered by a small piston which strikes a bell, creating a propulsive effect which drives it forwards through the water.
Dr Gabriel Weymouth, associate professor in Southampton University's school of engineering, said divers were currently deployed to carry out tasks that the invention could do instead.
"Where we're looking at things that are sensitive, or expensive or delicate, all of those are really problematic. Right now we always send divers into those situations, because you just can't trust underwater vehicles,
"If there's anything that you want to make sure not to break, then you just make sure not to put your underwater vehicle anywhere near it," he said.
One good example could be conservation projects which involve the application of a preservative or medicinal substance to coral, which would currently rely on human divers but could instead use soft-shelled robots, he said.
The robot has been tested in a tank but has not yet been used in the ocean due to the challenge of controlling it underwater, a particular challenge for soft robots which can be buffeted by currents.
Dr Weymouth said his team was working to solve this problem and he hoped that it could be overcome in the next couple of years.
"There are still many challenges and exciting possibilities to explore with soft underwater robotic technologies.
"We are now looking to extend the concept behind this robot to a fully manoeuvrable and autonomous underwater vehicle capable of sensing and navigating its environment," he said.
The design is also significantly more efficient than a propeller-powered craft, matching the "cost of transport" of the Aurelia aurita or "moon" jellyfish, which expends less energy for each movement than any other animal.
When the resonance created by the piston and bell reaches the ideal frequency the robot can move at one body length per second, while matching the efficiency of its natural counterpart.
Underwater drone craft are still a nascent technology, but their use in environmental and conservation projects has recently been demonstrated by the Schmidt Ocean Institute, a non-profit founded by former Google chief executive Eric Schmidt and his wife Wendy.
In October their craft SuBastian explored an underwater coral skyscraper taller than the Empire State Building found in the Great Barrier Reef.