Interesting article


2 Jun 2008
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Cape Town
Geesh, that's very interesting. Thanks for sharing this...

Reef Maniac

Yellow Tang
15 May 2007
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Sponges mainly live in the sea, and are extremely primitive organisms. They lack muscles, nerves and internal organs, for example, and are essentially a diverse set of cells supported by a hard exoskeleton

Two of the three major types of sponge build their skeletons using special structures called spicules. These are made from silica and are basically glass rods. Previous experiments suggested that light can pass along these structures

Now, Franz Brummer, of the University of Stuttgart, and colleagues have proved that living sponges use these internal glass rods as light conductors.
Light reaching the surface of the sponge is reflected off the insides of each spicule in much the same way light bounces along the inside of a fibre optic cable used to transmit electronic data. In doing so, light is beamed deep into the sponge

Brummer's team made the discovery using living sponges of the species Tethya aurantium. They collected the sponges from shallow waters off the coast of Croatia, and then transferred them to tanks of seawater.
They then implanted light sensitive paper deep inside each sponge. They did so under dark conditions and then exposed the surface of the sponge to light. When they checked the paper, they found it was covered in spots, which corresponded exactly with where light would exit each spicule.

In a control experiment, the researchers tested another sponge that does not grow using glass spicules. No light entered deep within it, showing that spicules are necessary to transmit the light.

I wonder if leather corals don't do the same - they also have long, narrow spicules in their bodies...


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