UO oceanographer Kelly Sutherland has swum with tiny colonial jellyfish unlike the type people normally see at a beach. She's scooped them out of the water with cups and studied them. Now she says that the way these jellies maneuver could inspire new-generation propulsion for undersea vehicles.
In the Sept. 2 issue of Nature Communications, a five-member team working under a National Science Foundation grant to Sutherland documents how these barely jellies — colonial siphonophores known scientifically as Nanomia bijuga — propel themselves through the water.
The bodies of these jellies generally are no more than 2 inches long. They are considered colonial because they are made up of separate but genetically identical units, each of which has a swimming jet that shoots water used for propulsion. The animal coordinates the firing of the jets to guide it where it wants to go.
"The younger swimming bells at the tip of the colony are responsible for turning," said Sutherland, who has appointments with the Oregon Institute of Marine Biology and Clark Honors College. "They generate a lot of torque. The older swimming bells toward the base of the colony are responsible for thrust."
Their tentacles capture zooplankton, the tiny organisms that these jellyfish consume, she added.
The jellies were gathered in the water off Friday Harbor on San Juan Island in Washington. Back in Sutherland's UO lab, researchers used high-speed digital photography and laser lighting to capture the jellies' movements.
"This is a very interesting system for studying propulsion because these jellies have multiple swimming bells to use for propulsion," Sutherland said. "This is relatively rare in the animal kingdom. Most organisms that swim with propulsion do so with a single jet. These siphonophores can turn on a dime, and very rapidly."
Information on the biomechanics of a living organism that uses such a coordinated system ought to inspire "a natural solution to multi-engine organization that may contribute to the expanding field of underwater-distributed propulsion vehicle design," the co-authors conclude in their paper.
For more details, read the full UO news release.
—By Jim Barlow, Public Affairs Communications