Glowing Snail: Scripps studies bizarre illuminating mollusk

This was a fun piece of news that caught my eye from the Scripps Institution of Oceanography in San Diego, California. It seems there is a small sea snail that can produce bioluminesence, strong enough with which it can illuminate the entire shell.

Researchers Dimitri Deheyn and Nerida Wilson have studied a particular species of "clusterwink snail" which has the ability to produce light but uses it in a way that is different from other bioluminescent creatures. Typically, bioluminesence is more focused - a dangling light lure atop a deep sea angler fish, a row of lights along a fish's lateral line, or literally a pair of high beams under the eyes. But with this particular snail, the light is emitted in all directions and the shell adds to the overall effect.

"It's rare for any bottom-dwelling snails to produce bioluminescence," Wilson said. "So its even more amazing that this snail has a shell that maximizes the signal so efficiently."

In a paper published in the Proceedings of the Royal Society B (Biological Sciences), the researchers theorized that the bioluminesence acted as a kind of "burglar alarm" triggered at the presence of a predator. The diffusion of the light caused by the shell perhaps makes the snail look bigger than it is and therefore a less appealing easy catch for a hungry crab or shrimp. The researchers are interested in the implications of how light can be transmitted through various materials, like the shell. Also curious is one of the study's funders, the U.S. Air Force, who would be interested in how this research could perhaps provide new approaches to better illuminate instruments and aircraft data readouts.

"Our next focus is to understand what makes the shell have this capacity and that could be important for building materials with better optical performance," said Deheyn.

Military applications aside, I find it very fascinating. It reminds me of the various little "glow-in-the-dark" plastic critters I had as a kid that would illuminate my room when the lights went out. But nature's parlor tricks are always way cooler.

Read the Scripps news release on the glowing snail.

Ocean's Lady of Light: scientist studies wonders of bioillumination

Bioluminesence: the ability of animals to generate light. We've seen it from fireflys to deep sea creatures to the flashing green dynoflagellates churned up in the night's crashing waves. It is an internal chemical reaction that provides many animals with unique ways to hunt, communicate, reproduce, or basically just get around in the dark. What is interesting is how much ocean life depends on bioluminesence. And scientists continue to learn more about this marvelous capability.

Dr. Edith Widder has been studying bioluminesence for over a decade, first as a grad student up to today as she continues her work as president and senior scientist of ORCA (Ocean Research and Conservation Association). Recently featured in Scientific American, Widder's passion for all things aglow underwater began with her studies in neurobiology and the light-producing plankton, dynoflagellates, that produces the emerald green light seen in the evening surf or wrapped around racing dolphins that leaves long green torpedo trails. (I often enjoy turning my dive light off during a night dive and follow my dive buddys by the light trails they give off from the action of their dive fins.)

Dr. Widder became forever hooked on bioluminesence when she had the opportunity to dive to 800 feet using a WASP - a high-tech cross between a deep sea diving suit, similar to the Newt or JIM suits, and a submersible. Scientific American quoted her reaction, "'I was trying to take some readings with a meter,' Widder says, 'when suddenly the whole inside of the suit lit up blue.' Widder had brushed up against a chain of siphonophores—a colony of jellyfish relatives—sparking their light show. 'It was breathtaking, absolutely breathtaking.'"

She has gone on to design remote camera platforms and other devices to film and observe deep sea bioluminescent organisms in their natural state - unperturbed by large submersibles or dive suits - gaining more insight as to an animal's day-to-day (or should I say, night-to-night) use and purpose for this fascinating function of nature.

According to Widder, there is much more bioluminesence taking place underwater than most people would suspect. If you were to trawl a net from 3000 meters to the surface, over 90% of your catch would be creatures capable of bioluminesence. And Widder has found some pretty unusual examples:

• The cookie cutter shark is able to hide itself from predators or potential prey swimming underneath with a bioluminescent stomach that matches the light coming from above, a technique called counterillumination.
• The scaleless dragonfish can emit and perceive red light - one color that is not typical for bioluminescent animals because of its short wavelength which limits its effectiveness. But this red light capability gives the dragonfish an advantage, allowing it to see potential prey before the prey sees the dragonfish.
• Then there is the deep open-ocean octopus that Widder recently discovered, whose suckers, not needing to cling to a rocky bottom, have evolved into light organs to attract potential prey.

Widder continues her work at ORCA and gives lectures and presentations to many academic and scientific organizations to illuminate the rest of us to the amazing world of bioluminesence. Here is a presentation Dr. Widder gave at TED this past April:



Dr. Widder notes that the study of bioluminesence is not just a look at something fascinating, that there are some very practical applications for ocean conservation, "We are using bioluminescence in a number of different ways to protect the ocean. We are using bioluminescent bacteria to detect toxins in ocean sediments, develop pollution gradient maps and perform water quality monitoring. Since bioluminescence in bacteria is directly linked to the respiratory chain, anything that depresses respiration—like toxins—depresses illumination. That way, we can tell you exactly how unhealthy a sediment is."

Read more about Dr. Edith Widder in Scientific American.
View her April, 2010 presentation at TED.

Seen & Unseen: Dave Gallo talks about some of the ocean's amazing ways

Here's just a little reminder - a fun one - as to why the ocean and all the animals that call it home need our support in conserving and protecting this vital environment. David Gallo, Director of Special Projects for the Woods Hole Oceanographic Institution, is a great speaker and puts on presentations that always leave the audience in awe and amazement. Here is a wonderful video clip from 2007 given at a TED meeting (TED is an interesting organization, dedicated to Technology, Entertainment, and Design - which means a wide range of fascinating speakers and subjects):

Bioluminescence in the greater depths and a cephlapod's camouflage through manipulation of skin color and texture - two of nature's fascinating ways it perpetuates life in the aquatic kingdom.