Jellyfish and lampreys teach scientists a lesson about motion while debunking the previously held assumption that underwater motion is propped by pushing against the liquid.
Both jellyfish and lampreys are highly efficient swimmers. Their motion has been observed to be highly energy efficient. The mechanism that allows them to move so swiftly has been wrongly understood until now.
New research led by Doctor Brad Gemmell of the University of South Florida and assistant professor with the Department of Integrative Biology sheds new light on this exact mechanism. In an unexpected shift, the research team reveals that jellyfish and lampreys don’t apply pressure on the water. Instead, they create a vacuum above, pulling their bodies upwards in this case.
This revolutionary breakthrough is crucial to further understanding the evolution of these marine animals, as well as their ecological impact. Furthermore, robotics and underwater vehicles could largely benefit from these findings.
Doctor Gemmell explained:
“Given our findings, we may have to rethink our ideas about some of the evolutionary adaptations acquired by swimming animals and how we approach vehicle design in the future”.
The study appears in Nature Communications and describes the experiments conducted by the research team. Emerged in a large water tank, the jellyfish and lampreys have been observed with the help of high-definition cameras, recording every millisecond of their movement.
To better track their movements, the researchers added glass beads to the water tank, illuminating them with the help of a laser. As the jellyfish and lampreys moved through the water tank, the beads reacted to each movement in concert. With the use of the high speed recording cameras, the researchers could observe the hydrodynamic efficiency of the jellyfish and lampreys.
Previous studies have observed the pressure underneath the top umbrella of jellyfish. This time, it was observed that it is in fact the low-pressure pocket created on top of the umbrella that allows jellyfish to move so efficiently while wasting so little energy.
Low pressure is the key word to understand how jellyfish and lampreys teach scientists a lesson about motion. The marine environment dwellers use low pressure to pull themselves forward through the low-pressure pockets.
Photo Credits: Pixabay