It is a gentler way to grab soft-bodied specimens and an easier way for scientists to study these creatures. But how do you retrieve such delicate organisms without damage?
The answer lies in the Japanese art of origami. Inspired by the traditional paper-folding techniques, engineers and marine biologists have designed a 3D printed, 12-sided origami trap that can fold gently and around unsuspecting sea creatures. The device (which is known as the rotary actuated dodecahedron, or RAD for short) can be attached to the arm of an underwater rover and triggered remotely to capture soft marine life safely.
The device has been successfully tested, by trapping a small squid, octopuses and jellyfish at a depth of 700 meters in the ocean. The design is robust enough to work at depths of up to 11 kilometres, and it could easily be scaled up to target larger organisms.
This is the key to exploring the ocean, and devices like suction samplers (which literally hoover up samples from remote rovers) can target specific organisms, but they can still damage delicate lifeforms. This means that the study of soft-bodied creatures, like jellyfish, comb jellies and tunicate has been "neglected" says David Gruber, a marine biologist who helped design RAD. Gruber also says that with the help of new technology, we are just beginning to understand the vital role such creatures play in the ocean ecosystem. "Globally, gelatinous zooplankton is estimated to constitute a biomass of more than 38 billion kilograms of carbon," he points out. That’s roughly 7% of the world’s total biomass (the dry weight of living organisms) or more than 100 times the total biomass of humanity.
Designing the RAD was definitely a mission for the team and tough to develop, due to the device being full of small but important design touches. For example, there are gaps left between the panels of the dodecahedron in order to stop pressure from building up in the interior when the marine rover makes the trip from the bottom of the ocean to the surface. The edge of the panel is also softer than the durable plastic in the main body.
According to Harvard University mechanical engineer, Zhi Ern Teoh, the main challenge was getting the origami to unfold using just a single motor. In order to do so, the system has fewer points of failure and can be folded and unfolded with a single command. However, it meant Teoh and his peers had to design a complex series of linkages that connects each of the device's 12 panels back to the central motor. This had to be light enough not to strain the motor and robust enough not to break mid-mission.
This origami device is just one method that's being explored for the capture of soft-bodied marine life. One big advantage of this design is that its potential for modification. As mentioned above, the mechanism could be scaled up to just about any size, allowing it to capture larger species.
While the RAD is currently manually operated, it could also be turned into an automated trap which lures sea creatures and sensors to detect when they're in the right position to be grabbed.