Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Surf's up: Turbulence tells sea urchins to settle down

10.04.2013
Tumbling in the waves as they hit a rocky shore tells purple sea urchin larvae it's time to settle down and look for a spot to grow into an adult, researchers at the University of California, Davis, Bodega Marine Laboratory have found. The work is published April 8 in the journal Proceedings of the National Academy of Sciences.
"How these animals find their way to the right habitat is a fascinating problem," said Brian Gaylord, professor of evolution and ecology at UC Davis and a researcher at the Bodega Marine Lab. "The turbulence response allows them to tell that they're in the right neighborhood."

Like most shoreline animals, purple sea urchins (Strongylocentrotus purpuratus) have a two-stage life cycle. The young are microscopic, look completely different from adults and drift in the upper levels of the ocean for about a month before settling on a rocky shore and transforming into the familiar spiny adult.

"Once they decide to settle, they attach to a rock and undergo body remodeling into a juvenile sea urchin with spines," Gaylord said.

Over short distances, the larvae can respond to chemical traces in the water, especially substances that might be given off from a rock thick with algae or other food for the growing urchins.

But how do the larvae know they are close enough to the right shoreline habitat to start searching for such signals?

On the California coast, rocky headlands — the urchins' preferred environment — are interspersed with long stretches of beach that experience lower levels of turbulence. The larvae don't have the resources to swim for miles along a beach looking for a nice slimy rock, but when carried by currents near a wave-swept rocky reef, the high turbulence tells them to begin a finer-scale search, the researchers found.

Gaylord and co-authors Jason Hodin of Stanford University's Hopkins Marine Station and Matthew Ferner of San Francisco State University used a device called a Taylor-Couette cell to see how urchin larvae responded to being churned by shear forces comparable to those in waves breaking on a rocky shore.

The Taylor-Couette cell consists of one rotating cylinder inside another, with a layer of fluid in between. When the cylinders spin relative to each other, they set up shear forces in the fluid. Scientists more typically use the device for studying fluid dynamics, especially the transition where flows becomes chaotic and turbulence appears.

Gaylord and his colleagues took the urchin larvae for a spin through a Taylor-Couette cell then exposed them to potassium, known to act as a chemical signal that triggers larvae to begin settling.

Larvae that had been exposed to turbulence responded to the chemical signal earlier in development than those that had not — in fact, they responded at a stage at which it had previously been believed larvae could not settle.

Especially telling was that neither turbulence nor the chemical signal alone promoted settling at this earlier developmental stage.

The experiment shows that the shift from living free in the ocean to living on a rock is a two-step process, Gaylord said. In the first step, exposure to turbulence initiates an abrupt transition to a state in which the larvae are "competent to settle." A chemical signal triggers the second step, actual settlement, and the larvae then complete their transformation into juvenile sea urchins.

It's not yet clear how the larvae detect turbulence, Gaylord said. That might happen through receptors that respond to stretching or flexing. The two-step settlement process might occur in other species that settle on shorelines, he said.

The work was supported by the National Science Foundation and the National Oceanic and Atmospheric Administration.
About UC Davis

For more than 100 years, UC Davis has engaged in teaching, research and public service that matter to California and transform the world. Located close to the state capital, UC Davis has more than 33,000 students, more than 2,500 faculty and more than 21,000 staff, an annual research budget of nearly $750 million, a comprehensive health system and 13 specialized research centers. The university offers interdisciplinary graduate study and more than 100 undergraduate majors in four colleges — Agricultural and Environmental Sciences, Biological Sciences, Engineering, and Letters and Science. It also houses six professional schools — Education, Law, Management, Medicine, Veterinary Medicine and the Betty Irene Moore School of Nursing.
Media contact(s):
Brian Gaylord, Bodega Marine Laboratory, (707) 875 1940, bpgaylord@ucdavis.edu
Andy Fell, UC Davis News Service, (530) 752-4533, ahfell@ucdavis.edu

Andy Fell | EurekAlert!
Further information:
http://www.ucdavis.edu

More articles from Life Sciences:

nachricht Neural efficiency hypothesis confirmed
28.07.2015 | ETH Zurich

nachricht Scientists study predator-prey behavior between sharks and turtles
28.07.2015 | University of Miami Rosenstiel School of Marine & Atmospheric Science

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Superfast fluorescence sets new speed record

Plasmonic device has speed and efficiency to serve optical computers

Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.

Im Focus: Unlocking the rice immune system

Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight

A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...

Im Focus: Smarter window materials can control light and energy

Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.

By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for...

Im Focus: Simulations lead to design of near-frictionless material

Argonne scientists used Mira to identify and improve a new mechanism for eliminating friction, which fed into the development of a hybrid material that exhibited superlubricity at the macroscale for the first time. Argonne Leadership Computing Facility (ALCF) researchers helped enable the groundbreaking simulations by overcoming a performance bottleneck that doubled the speed of the team's code.

While reviewing the simulation results of a promising new lubricant material, Argonne researcher Sanket Deshmukh stumbled upon a phenomenon that had never been...

Im Focus: NASA satellite camera provides 'EPIC' view of Earth

A NASA camera on the Deep Space Climate Observatory (DSCOVR) satellite has returned its first view of the entire sunlit side of Earth from one million miles away.

The color images of Earth from NASA's Earth Polychromatic Imaging Camera (EPIC) are generated by combining three separate images to create a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Euro Bio-inspired - International Conference and Exhibition on Bio-inspired Materials

23.07.2015 | Event News

Clash of Realities – International Conference on the Art, Technology and Theory of Digital Games

10.07.2015 | Event News

World Conference on Regenerative Medicine in Leipzig: Last chance to submit abstracts until 2 July

25.06.2015 | Event News

 
Latest News

Neural efficiency hypothesis confirmed

28.07.2015 | Life Sciences

Scientists study predator-prey behavior between sharks and turtles

28.07.2015 | Life Sciences

Tropical deforestation releases large amounts of soil carbon

28.07.2015 | Agricultural and Forestry Science

VideoLinks
B2B-VideoLinks
More VideoLinks >>>