Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New research on seaweeds shows it takes more than being flexible to survive crashing waves

11.05.2012
Bladed and branched algae adapted to strong wave conditions are able to reconfigure their shape and size

Seaweeds are important foundational species that are vital both as food and habitat to many aquatic and terrestrial shore organisms.


This image shows seaweeds reconfiguring in flow, viewed from downstream.
Credit: Courtesy of Patrick Martone, University
f British Columbia

Yet seaweeds that cling to rocky shores are continually at risk of being broken or dislodged from their holds by crashing waves with large hydrodynamic forces. So how do such seaweeds survive in intertidal zones? Do they have special properties that make them extremely flexible or particularly strong?

Patrick Martone (University of British Columbia) has spent a considerable amount of time standing on the shore watching big waves crash against intertidal rocks and wondering how the seaweeds—or anything else—manage to survive there.

"Many animals can run and hide when storms roll in and the waves increase," Martone observes. "But seaweeds don't have that option; they have to just hold on tight and face the waves head-on."

Indeed, the drift algae that pile up on the beach after a big storm suggest that not all algae are able to survive such onslaughts.

"So what is special about the ones that do survive?"

Previous research has found that one solution seaweeds have come up with is flexibility. Blades of seaweed may curl up and branches may collapse, thereby changing the shape of the seaweed and reducing drag as water velocity increases. But different seaweeds may utilize different strategies to effectively reduce drag, such that some may be better at changing shape and others at reducing size. Martone and colleagues from Stanford University and St. John Fisher College were interested in teasing apart some of these variables and published their findings recently in the American Journal of Botany.

By exploring the dynamics of size and shape changes of intertidal seaweeds at different rates of water flow, Martone and co-authors hoped to better understand the various strategies that have led to the morphological diversity in macroalgae seen along wave-swept shores.

The authors collected fronds from six different species of algae (four branched, two bladed) along the intertidal zone of the central Californian coast, placed them in a recirculating water flume, and measured the drag they experienced and the changes in shape and size they underwent under 15 different rates of water flow, ranging from 0 to 4 m/sec.

Interestingly, they found that while all six species of seaweed underwent severe reconfiguration as water velocity increased—thus limiting the drag they would otherwise experience if they were rigid—the two types of algae accomplished this in slightly different ways.

"Unbranched algae seem to be 'shape changers,' reducing drag primarily by folding and collapsing in flow," notes Martone. "Certain branched algae, on the other hand, are 'area reducers,' compensating for drag-prone shapes by reducing frond size through branch reorientation and compression. Thus, we demonstrate that flexibility acts in two distinct ways: permitting wave-swept algae to change shape and to reduce frond area projected into the flow."

Martone and colleagues also wanted to see how accurately responses at slow speeds of water flow could be extrapolated to what happens at higher speeds, such as what the seaweeds might be experiencing along the shore.

"Most structural engineers have it easy," Martone says. "Studying air flow around airplane wings or water flow around bridges is relatively straightforward, since these man-made structures are rigid and do not deform in flow. Seaweeds are more complicated because they are flexible. As flow speeds increase, flexible seaweeds re-orient and reconfigure, changing size and shape to reduce drag, making predictions much more difficult."

Indeed, the authors found that measurements extrapolated out from lower speeds did not always match those observed at higher speeds, making it tricky to predict what would happen at higher water velocities. Moreover, in the experimental water flume seaweeds may have more time to react to water speeds that are relatively slow compared with breaking waves—a condition whereby fast reaction times may be crucial for reconfiguring and reducing drag.

"Understanding how selection can act on the ability to change shape or the ability to reduce size in flow may give us insight into the morphological evolution of intertidal algae," summarizes Martone.

Martone concludes that further investigation is still needed to tease these features apart: "We have started building flexible models of branched and unbranched seaweeds in the lab to explore how precise changes in branching affect drag. We hope this work will help us better understand how waves have sculpted seaweeds over evolutionary time."

Patrick T. Martone, Laurie Kost, and Michael Boller. 2012. Drag reduction in wave-swept macroalgae: Alternative strategies and new predictions. American Journal of Botany 99(5): 806-815. DOI: 10.3732/ajb.1100541

The full article in the link mentioned is available for no charge for 30 days following the date of this summary at http://www.amjbot.org/content/99/5/806.full.pdf+html. After this date, reporters may contact Richard Hund at ajb@botany.org for a copy of the article.

The Botanical Society of America is a non-profit membership society with a mission to promote botany, the field of basic science dealing with the study and inquiry into the form, function, development, diversity, reproduction, evolution, and uses of plants and their interactions within the biosphere. It has published the American Journal of Botany for nearly 100 years. In 2009, the Special Libraries Association named the American Journal of Botany one of the Top 10 Most Influential Journals of the Century in the field of Biology and Medicine.

For further information, please contact the AJB staff at ajb@botany.org.

Richard Hund | EurekAlert!
Further information:
http://www.botany.org

More articles from Life Sciences:

nachricht A novel socio-ecological approach helps identifying suitable wolf habitats
17.02.2017 | Universität Zürich

nachricht New, ultra-flexible probes form reliable, scar-free integration with the brain
16.02.2017 | University of Texas at Austin

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Switched-on DNA

20.02.2017 | Materials Sciences

Second cause of hidden hearing loss identified

20.02.2017 | Health and Medicine

Prospect for more effective treatment of nerve pain

20.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>