Exploration of the depths of the ocean is still an incredibly difficult technical challenge. The colossal pressure requires the use of special underwater vehicles, often piecemeal and expensive. At the same time, many marine animals feel completely normal here, forcing scientists to think over and over again about how to use their "superpowers" for the benefit of science.
A new such project was recently presented by John Dabiri and Nicole Xu of Stanford University. In an article published in the journal Science Advances, they propose equipping deep-sea jellyfish with sensors and flexible electrodes. By stimulating the movement of animals, the electrodes allow them to be guided and even accelerated up to a speed three times faster than usual.
Previously, whales, dolphins and some other marine animals were already used as carriers of miniature sensors for monitoring the ocean. However, scientists could not control their movements in any way and had to rely on where the whale or dolphin decided to go.
It would seem easier to control relatively primitive jellyfish, and ethical issues for creeping are far from being as acute as for mammals. However, unlike dolphins or whales, jellyfish do not have pain receptors. Therefore, it is necessary to stimulate their muscles directly, forcing them to contract under the influence of weak electrical discharges, much like the artificial drivers of the heart work.
Demonstrating this approach, Dabiri and Xu implanted a mass of microelectrodes into the body of the jellyfish. Tiny control modules made one or the other group of electrodes to work rhythmically, causing contractions of the corresponding muscle groups and forcing the jellyfish to move. Apparently, the animals themselves were not worried about this: they looked and behaved quite normally, and the discharge of fluid, characteristic of stressed jellyfish, did not occur.
Experiments have shown that when the rhythm is accelerated, the animal can move even faster than usual. This movement was surprisingly effective. In theory, accelerating three times should require nine times the metabolic rate. However, the measurements of oxygen consumption carried out in the laboratory showed that the energy exchange in the jellyfish, which the new system makes to swim three times faster, only doubles.
The question arises why jellyfish have not developed such a fast and efficient movement in nature. Perhaps they simply did not experience sufficient evolutionary pressure: these animals do not have too many natural enemies at depth, and there is no particular need to spend energy on fast movement.