By Christina DiCenzo. Mentored and edited by Priyanka Runwal
The dark depths of our ocean remain largely unexplored, making it one of the most mysterious and poorly understood regions on Earth. Satellite observations cannot penetrate too far below the ocean’s surface. Gliders and other autonomous underwater vehicles are clunky to navigate and often require massive amounts of energy—and money—to power themselves through the depths. John Dabiri, an aeronautical engineer at the California Institute of Technology, however, thinks he’s discovered the perfect way to take the plunge – cyborg jellyfish.
Jellyfish are found in oceans worldwide, from the tropics to the poles, and from the surface waters to the deep seas. They reproduce quickly and are among the most abundant creatures in our seas. Although they appear to drift dreamily, jellyfish are extremely efficient swimmers, mathematically shown by Dabiri’s research team to outperform a host of other marine critters.
Dabiri wanted to leverage their widespread presence and swimming skills to explore the deep sea. But there was one problem: Although efficient, jellyfish aren’t fast.
To make these gelatinous creatures swim speedily, Dabiri and his team crafted a cyborg jellyfish. They began by implanting wire electrodes onto a live jellyfish’s umbrella-shaped bell. A control system attached to the center of the jellyfish’s body powers these electrodes. Electric pulses flow through the electrodes, prompting the jellyfish’s bell muscles to contract at a regular pace. This contrasts their natural movement, where the opening and closing of the bell is irregular and punctuated with extended periods of floating leisurely.
The researchers tested this cyborg jellyfish’s abilities by recording the time it took for the creature to swim from the surface to the bottom of the vertical tank. They found that the prosthetic-equipped jellyfish swam three times faster than normal and the power required to fuel it was 10 to 1,000 times lower than that required by existing swimming robots. That’s because most of the energy the jellyfish need comes from feeding on a variety of food flitting through the ocean. More importantly, when jellyfish swim, they contract their bell muscles and push out water behind them, producing a whirlpool-like pattern called vortex ring that thrusts the jellyfish forward. As this vortex ring travels down and the jellyfish ascend while sucking in surrounding water, the ring provides more propulsion and allows for energy-efficient swimming.
But swimming fast and efficiently isn’t enough. Dabiri also hopes to control the direction in which these jellyfish move, especially so they can navigate the perilous seafloor terrain. “It’s trying to steer jellyfish in the same way we steer horses or cattle for agriculture,” he said during a Feb. 18 session at the American Association for the Advancement of Science annual meeting.
While a steering system is in development, a larger question looms: is it ethical to hijack a living organism and control its movements?
Dabiri asks us to consider the jellyfish’s natural biology. These creatures don’t have a brain or pain receptors. That means they can’t feel the electrodes or interpret the electrical pulses as pain. Jellyfish secrete mucus when stressed, but the absence of such stress-induced slime over the course of Dabiri’s experiments indicated that the microelectronics do not harm these invertebrates.
But before we hitch all our hopes on these cyborg jellies, they have to hack it in the real world. Dabiri’s team has only tested the jellyfish in the highly controlled setting of his laboratory rather than the open ocean. They’re yet, for instance, to mount environmental sensors that measure ocean temperatures and salinity onto these creatures and figure out ways to retrieve such data from the jellyfish at large.
Once these challenges are addressed, the dream is for Dabiri’s cyborgs to become commonplace. The necessary electronics to create a cyborg jellyfish can be purchased cheaply and easily over the internet. “I think there is a lot of innovative science that is just not happening today because people can’t afford to explore the ocean,” Dabiri said. “We’re excited about the idea of democratizing ocean exploration.”
Christina DiCenzo is a graduate student at the University of Rhode Island studying environmental communication. She works at the Rhode Island 4-H Program where she plans science education programs for children of all ages. She has interned at the Metcalf Institute for Marine & Environmental Reporting and is co-author of the Inclusive Science Communication Starter Kit. Email Christina at dicenzochristina@gmail.com.
Image: Live jellyfish are fitted with microelectronics that stimulate fast and efficient swimming. Credit: California Institute of Technology
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