Light Inside Sponges: Sponges Invented (and Employed) The First Fiber Optics

Three of the numerous needle bundles in Tethya are shown here. (Credit: University of Stuttgart / Zoology)

Fiber optics as light conductors are obviously not just a recent invention. Sponges (Porifera) -- the phylogenetically oldest, multicellular organisms (Metazoa) -- are able to transduce light inside their bodies by employing amorphous, siliceous structures.

Already more than ten years ago, the finding of photosynthetically active organisms inside sponges raised the question, how they could survive there in an otherwise presumably dark space. Already at that time, the marine biologists Elda Gaino and Michele Sarà from Genova, Italy, hypothesized, that light might be transferred inside the sponge body.

Marine zoologists from the University of Stuttgart, and from the Leibnitz Institute for Marine Sciences at the University of Kiel, both within the research project BIOTECmarin, could now show, that the siliceous skeletal elements (spiculae) of the marine sponge Tethya aurantium in fact can transduce light, and do so in living sponges.

Sponges without those spicules -- like the aspicular sponge Aplysina aerophoba -- are not able to transport light inside their tissue. In their latest research, the scientists from Stuttgart and Kiel are the first to demonstrate light transduction inside living sponges. Until now light transduction could only be shown in explanted single spicules after laser illumination.

The authors Franz Brümmer, Martin Pfannkuchen, Alexander Baltz, Thomas Hauser and Vera Thiel published these exciting results in the Journal of Experimental Marine Biology and Ecology with the title: Light inside sponges.

Journal reference:

1. Brümmer et al. Light inside sponges. Journal of Experimental Marine Biology and Ecology, 2008; DOI: 10.1016/j.jembe.2008.06.036

Adapted from materials provided by University of Stuttgart, via AlphaGalileo.
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