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

Video On the Scene: In Gaza, Darkness Brings Dread and Death

Palestinians fear nighttime raids, many feel abandoned by outside world, VOA's Scott Bobb reports More

African Small Farmers Could Be Key to Ending Food Insecurity

Experts say providing access to microloans, crop insurance, better storage facilities, irrigation, road systems and market information could enable greater production More

University of Michigan Wins Solar Car Race

Squad guided its student-designed solar-powered vehicle to fifth consecutive time victory in eight-day bi-annual American Solar Challenge 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.
Gazans in Shelled School Sought Shelteri
X
Scott Bobb
July 30, 2014 8:16 PM
Israel's air and ground assault against Hamas-led fighters in Gaza has forced many Palestinians to flee their homes, seeking safety. But safe places are hard to find, as VOA’s Scott Bobb reports from Jabaliya.
Video

Video Gazans in Shelled School Sought Shelter

Israel's air and ground assault against Hamas-led fighters in Gaza has forced many Palestinians to flee their homes, seeking safety. But safe places are hard to find, as VOA’s Scott Bobb reports from Jabaliya.
Video

Video Rapid Spread of Ebola in West Africa Prompts Global Alert

Across West Africa, health officials are struggling to keep up with what the World Health Organization describes as the worst ebola outbreak on record. The virus has killed hundreds of people this year. U.S. President Barack Obama and other world leaders are watching the developments closely as they weigh what actions, if any, are needed to help contain the disease.
Video

Video Michelle Obama: Young Africans Need to Embrace Women's Rights

U.S. first lady Michelle Obama urged some of Africa's best and brightest to advocate for women's rights in their home countries. As VOA's Pam Dockins explains, Obama spoke to some 500 participants of the Young African Leaders Initiative, a six-week U.S.-based training and development program.
Video

Video Immigrant Influx on Texas Border Heats Up Political Debate

Immigrants from Central America continue to cross the U.S.-Mexico border in south Texas, seeking asylum in the United States, as officials grapple with ways to deal with the problem and provide shelter for thousands of minors among the illegal border crossers. As VOA's Greg Flakus reports from Houston, the issue is complicated by internal U.S. politics and U.S. relations with the troubled nations that immigrants are fleeing.
Video

Video Study: Latino Students Most Segregated in California

Even though legal school segregation ended in the United States 60 years ago, one study finds segregation still occurs in the U.S. based on income and race. The University of California Los Angeles Civil Rights Project finds that students in California are more segregated by race than ever before, especially Latinos. Elizabeth Lee reports for VOA from Los Angeles.
Video

Video Vietnamese Staging Chinese Product Boycott After Oil Rig Spat

China recently pulled an oil rig from an area of the disputed South China Sea that Vietnam also claims. Despite the action, the incident has had a lingering effect on consumers in Vietnam. VOA's Reasey Poch reports from Hanoi on an effort to boycott Chinese products.
Video

Video A Summer Camp for All the World

VIDEO: During workshops and social gatherings, the Global Youth Village summer camp encourages young people to cooperate and embrace their differences, while learning to communicate with people from other countries. VOA's Deborah Block has more.
Video

Video From Cantankerous Warlock to Incorruptible Priest, 'Harry Potter' Actor Embraces Diverse Roles

He’s perhaps best known as Mad Eye Moody, the whimsical wizard in the Harry Potter franchise. But character actor Brendan Gleeson's resume includes dozens of films, and he embraces all the characters he inhabits with equal passion. In an interview with VOA’s Penelope Poulou, Gleeson discussed his new drama "Calvary" and his secret to success.

AppleAndroid