News / Science & Technology

Jellyfish Could Be Ocean's Most Efficient Swimmers

Jelly Fish Lake is an ancient marine habitat containing millions of jellyfish on the island nation of Palau.
Jelly Fish Lake is an ancient marine habitat containing millions of jellyfish on the island nation of Palau.

Related Articles

New Fish Species is Electrifying

The discovery was made in the so called "lost world" of northeastern South America
VOA News
Those jellyfish you see seemingly floating and bobbing along with the waves have a secret.

New research shows the gelatinous creatures are among the best swimmers in the ocean, which could be an important reason they have been so successful as a species.

“We find that jellyfish exhibit a unique mechanism of passive energy recapture, which can reduce metabolic energy demand by swimming muscles,” write the researchers in the journal Proceedings of the National Academy of Sciences. “Contrary to prevailing views, this contributes to jellyfish being one of the most energetically efficient propulsors on the planet.”

Researchers said the results show why medusan swimmers – a name given to creatures like jellyfish that resemble Medusa of Greek mythology – thrive despite their simple body plan. They added that the research could have implications for bio-inspired design, where low-energy propulsion is required. Previous theories about the success of jellyfish assumed the creatures were able to adapt to changing water temperatures and take advantage of a decline in other potential predators due to overfishing.

Brad J. Gemmell at the Marine Biological Laboratory at Woods Hole in Massachusetts and a team of other researchers studied the movement of jellyfish with funding from the U.S. Navy, which had expressed interest in non-traditional propulsion.

The key to Gemmell’s findings lies with the jellyfish’s second thrust when moving. Scientist have long known jellyfish move by squeezing water through the bell that forms ahead of their body. Scientists have also understood that jellyfish derive some forward momentum when the bell refills with water, but until now, it hadn’t been understood how much propulsion this secondary thrust generates.

As it turns out, the second thrust accounts for 32 percent of the jellyfish’s forward movement, and the kicker is it requires no energy. It’s a purely mechanical movement, like a rubber band snapping back after being stretched.

The findings could lead to more efficient underwater robots that could ostensibly prowl the seas for years, sending back data.

Here's a video showing the propulsion derived from the jellyfish's secondary thrust:


(Video: Proceedings of the National Academy of Sciences)

In the first part of the video, an A. aurita jellyfish shows the velocity vectors and vorticity produced by swimming. Notice how the stopping vortex forms upstream and on the exumbrellar surface of the animal before recovery. The vortex ring then moves under the bell as its vorticity (energy) increases. The second part of the video shows instantaneous pressure field estimations along with body velocity to demonstrate a mechanistic explanation for how jellyfish can accelerate, and thus gain extra distance during a period of the swimming cycle in which there is no kinematic motion.
Instantaneous pressure field estimations are shown simultaneously with body velocity to demonstrate a mechanistic explanation for how jellyfish can accelerate, and thus gain extra distance, during a period of the swimming cycle in which there is no kinematic motion.

Read more at: http://phys.org/news/2013-10-reveals-jellyfish-efficient-swimmers-video.html#jCp

You May Like

Is Air Travel Safe?

Aviation expert says despite tragic losses of Malaysian Airlines flights 370 and 17, industry experienced lowest fatality rate in recorded history last year More

Multimedia 100 Days Later, Nigerian Girls Still Held

Activists holding rallies in Nigeria and several other countries to mark 100th day of captivity for more than 200 schoolgirls being held by Boko Haram More

Chocolate Too Bitter? Swap Sugar for Mushrooms

US food technology company develops fermentation process using mushrooms to reduce bitterness in cocoa beans, believes it will cut sugar content in candy More

This forum has been closed.
Comment Sorting
Comments
     
by: Cranksy from: USA
October 09, 2013 3:35 PM
Thank you for correcting the word "about" in the above article to able.


by: Deb from: Az
October 09, 2013 1:55 PM
Why are the people in china, or where ever that way, are they using a ...SHREDDER...to shred jellyfish into a billion lil pieces? That is so wrong, and counderdics with your story....hummmm?


by: Cranksy from: USA
October 09, 2013 1:23 PM
When I first read the words "unique mechanism of passive energy recapture" I thought what's so unique about a nap. "Previous theories about the success of jellyfish assumed the creatures were about to adapt...." How can a future adaptation explain current success?

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
US Carriers Suspend Travel to Israeli
X
Carolyn Presutti
July 23, 2014 1:21 AM
The United States is prohibiting American carriers from flying to Israel's airport in Tel Aviv for 24 hours, because of rising violence between Israel and Hamas militants. The action was announced on Tuesday, after a rocket fired by Hamas militants in the Gaza Strip landed near the airport. As VOA's Carolyn Presutti tells us, international officials soon may have to determine which combat zones are too dangerous for commercial flights.
Video

Video US Carriers Suspend Travel to Israel

The United States is prohibiting American carriers from flying to Israel's airport in Tel Aviv for 24 hours, because of rising violence between Israel and Hamas militants. The action was announced on Tuesday, after a rocket fired by Hamas militants in the Gaza Strip landed near the airport. As VOA's Carolyn Presutti tells us, international officials soon may have to determine which combat zones are too dangerous for commercial flights.
Video

Video NASA Focuses on Earth-Like Planets

For decades, looking for life elsewhere in the universe meant listening for signals that could be from distant civilizations. But recent breakthroughs in space technology refocused some of that effort toward finding planets that may harbor life, even in its primitive form. VOA’s George Putic reports on a recent panel discussion at NASA’s headquarters, in Washington.
Video

Video IAEA: Iran Turns its Enriched Uranium Into Less Harmful Form

Iran has converted its stockpiles of enriched uranium into a less dangerous form that is more difficult to use for nuclear weapons, according to the United Nations’ Atomic Energy Agency. The move complies with an interim deal reached with Western powers on Iran's nuclear program last year, in exchange for easing of sanctions. Henry Ridgwell reports for VOA from London.
Video

Video Relic of Saint Draws Catholics Worried About Immigration Issue

A Roman Catholic saint who is a figure of devotion for those crossing the border into the United States is attracting believers concerned about the plight of undocumented immigrants. Mike O'Sullivan reports from Los Angeles, where a relic of Saint Toribio has drawn thousands to local churches.
Video

Video US Awards Medal of Honor for Heroics in Bloodiest of Afghan Battles

U.S. combat troops are withdrawing from Afghanistan, on pace to leave the country by the end of this year. But on Monday, U.S. President Barack Obama took time to honor a soldier whose actions while under fire in Afghanistan earned him the Medal of Honor. VOA's Jeff Seldin has more from the Pentagon.
Video

Video Ukraine Rebels Surrender MH17 Black Boxes

After days of negotiations, a senior separatist leader handed over two black boxes from an airliner downed over eastern Ukraine to Malaysian experts early Tuesday. While on Monday, the U.N. Security Council unanimously demanded that armed groups controlling the crash site allow safe and unrestricted access to the wreckage.
Video

Video In Cambodia, HIV Diagnosis Brings Deadly Shame

Although HIV/AIDS is now a treatable condition, a positive diagnosis is still a life altering experience. In Cambodia, people living with HIV are often disowned by friends, family and the community. This humiliation can be unbearable. We bring you one Cambodian woman’s struggle to overcome a life tragedy and her own HIV positive diagnosis.
Video

Video Nature of Space Exploration Enters New Age

Forty-five years ago this month, the first humans walked on the moon. It was during an era of the space race between the United States and the Soviet Union. World politics have changed since then and -- as Elizabeth Lee reports -- so has the nature of space exploration.

AppleAndroid