Ok, there is this cool thing I see sometimes that I could never identify. I've heard it was ostracods, but no more info. I finally tracked down a very nice academic who gave me the skinny.


Hi Sebastian – That’s a great illustration and a great description of what is sometimes called “the string of pearls” phenomenon, but is actually the mating display of ostracods. Ostracods are tiny crustaceans, about the size of tomato seeds and they use their bioluminescence to attract mates in the same way that fireflies do. It’s a common phenomenon throughout the Caribbean and is usually best seen about one half hour after sunset or moonset. Male ostracods release their bioluminescent chemicals into the water as a string of dots. It’s a species-specific display - sort of a Morse code. The spacing of the dots in the water is unique to a particular species so females, recognizing the code for their own species, can swim to the end of a string of dots and know that they’ll find an eligible male. If you want to read a more scientific description of the phenomenon you can find it in:



Morin, J.G. (1986) "Firefleas" of the sea: Luminescent signaling in marine ostracode crustaceans. Florida Entomologist 69, 105-121.



The amazing thing about ostracods is that they will still produce light even after they’re dead. During WWII Japanese soldiers would carry dried ostracods as an emergency light source. There are some good pictures on page 64 and 65 of National Geographic Vol 140 July 1971.

Edie Widder







************************************************************************

Dr. Edith A. Widder

Director, Bioluminescence Department

Senior Scientist

Harbor Branch Oceanographic Institution

Oops, here is the description

Sometimes, when scuba diving off the island of Bonaire, my wife and I have witnessed a beautiful light show. We stumbled upon it a few years ago, on a night dive, when we turned off our lights, as we often do. Imagine our surprise to see a field of small.upwardly chasing strings of lights appear all around us. When we turned our lights back on to see what was making the light, we could detect nothing there. The phenomenon was repeatable, and I must say we probably spent a half hour making it occur. We found that by turing on our flashlights and sweeping the reef before turning them off, we would "excite" the creatures producing the effect, and there would be a plethora of them. It was sort of like looking on some great city from a high hill, except the lights moved upward in a slow "chase" with the lights on the bottom going out as the strand rose.

Please, no wiseguy cracks about the thread title.





(Message edited by seb on April 6, 2005)

OOOOOOoooooh! I love going diving with my string of pearls.....


tee hee

Mare

Neat! cb

Seb, great shot, we have seen them several times and wondered what it was. Thanks for sharing.

Brian, I made that shot up in photoshop out of whole cloth, I would love to get a shot of them, nobody has yet. I'll send along the info I got on these guys to you.

it's great to find out what they are! I was diving in Roatan, The Bay islands, Honduras... I heard about them and nobody there knew what they were... it was one of the most beautiful things I have ever seen, like fairy lights underwater, visible when the moon is very very low, I was truely dumb struck!
Shula