The swimming habits of gelatinous animals are inspiring underwater vehicle design

Biologists at the University of Oregon detected that multi-jet propulsion lets the animals switch between speed and efficiency. They report their findings in a paper published in Proceedings of the National Academy of Sciences.

Why this is important:

• Two different swimming styles of nanomia bijuga, a marine animal related to jellyfish, let the animal prioritize speed or energy efficiency, depending on its current needs, a team of University of Oregon researchers found.
• The UO team, led by marine biologist Kelly Sutherland and postdoctoral researcher Kevin Du Clos, report their findings in a paper published Nov. 28 in Proceedings of the National Academy of Sciences.
• The discovery could inform underwater vehicle design, helping scientists to build more robust vehicles that can perform well under a variety of conditions.

How it works:

• Nanomia bijuga swims via jet propulsion.
• A dozen or more squishy structures on its body pump water backwards to push the animal forward. It can control these jets individually, either syncing them up or pulsing them in sequence.
• “Most animals can either move quickly or in a way that’s energetically efficient, but not both,” said Sutherland. “Having many, distributed propulsion units allows Nanomia to be both fast and efficient. And, remarkably, they do this without having a centralized nervous system to control the different behaviors.”
• “It gives a framework for developing a robot that has a range of capabilities,” Du Clos said. For instance, an underwater vehicle could have multiple propulsors, and simple changes in propulsion timing could allow that one vehicle to move either quickly or efficiently as the need arises.
• The research was conducted at Friday Harbor Labs in Washington.
• The team is currently looking beyond Nanomia at other species of colonial swimmers, to figure out how diverse arrangements of swimming units influence animals’ movement.

Background

• Sutherland has studied jellyfish in the Pacific Ocean off the U.S. West Coast and Panama and in the Mediterranean Sea off France.
• In 2020, she was awarded $1.1 million over three years from the Gordon and Betty Moore Foundation. The award enabled Sutherland and her team to look for answers to additional questions related to swimming efficiency and to develop new tools for measuring data, such as cameras that can capture motion in 3D space.
• Sutherland Lab: https://www.sutherlandlab.org/

Resources:

• Oregon Institute of Marine Biology: https://oimb.uoregon.edu/
• Grant lets marine biologist pursue bioinspired study of jellyfish