Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Young researcher discovers source of disco clams' light show

25.06.2014

Silica nanospheres behind clams' mirrored lips

Four years after falling in love with the disco clam – a cute little mollusk known for its underwater light show – Lindsey Dougherty has discovered the secret of its mirrored lips.


The disco or electric clam, Ctenoides ales, continually flashes light along the lip margins of its mantle. UC Berkeley graduate student Lindsey Dougherty discovered that the mirrored lips are composed of packed nanospheres ideal for reflecting the blue light prevalent underwater.

Credit: Lindsey Dougherty, UC Berkeley

A dive instructor and University of California, Berkeley, graduate student, Dougherty first encountered the two-inch clam in 2010 while diving with her mother and sister in Wakatobi, Indonesia. She and her sister even did a bit of underwater disco dancing to the clam's flashing beat.

"I've dived with humpback whales and great white sharks," said Dougherty, who first learned to dive at age 14 and taught diving in Zanzibar. "But when I saw the disco clam, I was enamored. I said then, 'I'm going to do a Ph.D. on the disco clam.'"

... more about:
»Indonesia »clam »dive »lip »mollusk »structure »tropical »underwater

It didn't take long for her to confirm that the flashing was not, as most people assumed, a form of bioluminescence – a chemical reaction inside animals like plankton that produces light similar to that of a glow stick. Instead, she found, the edge of the clam's mantle lip is highly reflective on one side. When the clam unfurls its lip – typically twice a second – the millimeter-wide mirror is revealed and reflects the ambient light, like a disco ball.

In this week's issue of the British Journal of the Royal Society Interface, Dougherty reports the unusual and perhaps unique structure of this mirrored lip.

The inside of the clam's lip is packed with tiny spheres of silica, only 340 nanometers in diameter, that are ideal reflectors, particularly of the blue light that penetrates deeper into seawater than does red light. The outside of the lip contains no silica nanospheres, so when the lip is furled, no light is reflected.

By repeatedly unfurling and furling the lip, the clam produces a continual rippling light show. The non-reflective back of the lip strongly absorbs blue light, so it appears dark and makes the contrast between the sides even more striking.

Dougherty used high speed video, transmission electron microscopy, spectrometry, energy dispersive x-ray spectroscopy and computer modeling to study the detailed internal structure of the margin of the clam's lip. She was assisted by colleagues Roy Caldwell, UC Berkeley professor of integrative biology; Sönke Johnsen of Duke University; and N. Justin Marshall of the University of Queensland, Brisbane, Australia. She could find no other instance of animals using silica nanospheres as flashing reflectors, though the white color of several insects apparently comes from a layer of silica that reflects white light.

The big question, Dougherty said, is why the clam flashes at all.

Called Ctenoides ales and sometimes referred to as the electric clam, disco clams are found in tropical areas of the Pacific Ocean, living in crevices in reefs and typically in clusters of two or more. Light is dim and blue-green at the clams' typical depth, which ranges from 3 to 50 meters (10-150 feet), but their rippling mirrored lips are visible even without artificial illumination. Dougherty said the question she is exploring is whether the clam is trying to attract prey, mostly plankton, or other clams and potential breeding partners; or if it is trying to scare away predators.

In ongoing experiments in Caldwell's lab, she is studying the structure of the clam's eyes – all 40 of them – to see whether they can even see the disco light. She also is raising clams in tanks to determine if they signal one another visually or chemically, and is testing their responses to fake predators.

The field work was conducted at Lizard Island Research Station in Australia and the Raja Ampat Research and Conservation Centre and Lembeh Resort in Indonesia.

Robert Sanders | Eurek Alert!

Further reports about: Indonesia clam dive lip mollusk structure tropical underwater

More articles from Life Sciences:

nachricht Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory

nachricht How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>