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

Cambodia Seeks Official UN Maps for Vietnam Border

Notice of request comes as 2 countries open border talks Tuesday after a clash last month More

From South Africa to Vietnam, Cyclists Deliver Message Against Rhino Horns

Appalled by poaching they saw firsthand, sisters embark on tour to raise awareness in countries where rhino horn products are in demand More

Uber Wants Johannesburg Police Protection

Request follows recent protests outside ride-hailing service's Johannesburg office 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.
Getting it Done Beyond a Nuclear Deali
X
July 07, 2015 12:02 PM
If a nuclear deal is reached between Iran and world powers in Vienna, it will be a highly technical road map to be used to monitor nuclear activity in Iran for years to come to ensure Tehran does not make nuclear weapons. Equally as complicated will be dismantling international sanctions that were originally intended to be ironclad. VOA’s Heather Murdock talks to experts about the key challenges any deal will present.
Video

Video Getting it Done Beyond a Nuclear Deal

If a nuclear deal is reached between Iran and world powers in Vienna, it will be a highly technical road map to be used to monitor nuclear activity in Iran for years to come to ensure Tehran does not make nuclear weapons. Equally as complicated will be dismantling international sanctions that were originally intended to be ironclad. VOA’s Heather Murdock talks to experts about the key challenges any deal will present.
Video

Video Rice Farmers Frustrated As Drought Grips Thailand

A severe drought in Thailand is limiting the growing season of the country’s important rice crop. Farmers are blaming the government for not doing more to protect a key export. Steve Sandford reports from Chiang Mai, Thailand.
Video

Video Making Music, Fleeing Bombs: New Film on Sudan’s Internal Refugees

In 2012, Sudanese filmmaker Hajooj Kuka went to make a documentary among civil war refugees in Sudan’s Blue Nile and Nuba Mountains region. What he found surprised him: music was helping to save people from bombing raids by their own government. VOA’s Carolyn Weaver has more.
Video

Video 'From This Day Forward' Reveals Difficult Journey of Transgender Parent

In her documentary, "From This Day Forward", filmmaker Sharon Shattuck reveals the personal journey of her transgender father, as he told his family that he always felt he was a woman inside and decided to live as one. VOA’s Penelope Poulou has more.
Video

Video Floodwaters Threaten Iconic American Home

The Farnsworth House in the Midwest State of Illinois is one of the most iconic homes in America. Thousands of tourists visit the site every year. Its location near a river inspired the design of the house, but, as VOA’s Kane Farabaugh reports, that very location is now threatening the existence of this National Historic Landmark.
Video

Video Olympics Construction Scars Sacred Korean Mountain

Environmentalists in South Korea are protesting a Winter Olympics construction project to build a ski slope through a 500-year-old protected forest. Brian Padden reports that although there is strong national support for hosting the 2018 Pyeongchang Winter Olympics, there are growing public concerns over the costs and possible ecological damage at the revered mountain.
Video

Video Xenophobia Victims in South Africa Flee Violence, Then Return

Many Malawians fled South Africa early this year after xenophobic attacks on African immigrants. But many quickly found life was no better at home and have returned to South Africa – often illegally and without jobs, and facing the tough task of having to start over. Lameck Masina and Anita Powell file from Johannesburg.
Video

Video Family of American Marine Calls for Release From Iranian Prison

As the crowd of journalists covering the Iran talks swells, so too do the opportunities for media coverage.  Hoping to catch the attention of high-level diplomats, the family of American-Iranian marine Amir Hekmati is in Vienna, pleading for his release from an Iranian prison after nearly 4 years.  VOA’s Heather Murdock reports from Vienna.
Video

Video UK Holds Terror Drill as MPs Mull Tunisia Response

After pledging a tough response to last Friday’s terror attack in Tunisia, which came just days before the 10th anniversary of the bomb attacks on London’s transport network, British security services are shifting their focus to overseas counter-terror operations. VOA's Henry Ridgwell has more.
Video

Video Obama on Cuba: This is What Change Looks Like

President Barack Obama says the United States will soon reopen its embassy in Cuba for the first time since 1961, ending a half-century of isolation. VOA White House correspondent Luis Ramirez reports.
Video

Video Hate Groups Spread Influence Via Internet

Hate groups of various kinds are using the Internet for propaganda and recruitment, and a Jewish human rights organization that monitors these groups, the Simon Wiesenthal Center, says their influence is growing. The messages are different, but the calls to hatred or violence are similar. VOA's Mike O’Sullivan reports.
Video

Video Blind Somali Journalist Defies Odds in Mogadishu

Despite improving security in the last few years, Somalia remains one of the most dangerous countries to be a journalist – even more so for someone who cannot see. Abdulaziz Billow has the story of journalist Abdifatah Hassan Kalgacal, who has been reporting from the Somali capital for the last decade despite being blind.

VOA Blogs