SILICEOUS SPICULES OF TETHYA-SEYCHELLENSIS (PORIFERA) SUPPORT THE GROWTH OF A GREEN-ALGA - A POSSIBLE LIGHT CONDUCTING SYSTEM

In Tethya seychellensis (Wright), a demosponge collected on the coral reef of the Maldive Islands, algal filaments of the syphonaceous chlorophyte Ostreobium sp. were seen to penetrate deep into the sponge body. The filaments were in close association with the sponge skeleton, which consists of siliceous spicules. Filaments were arranged around the spicular bundles radiating from the central core of the sponge body into the outermost cortical region. In sponges like Tethya, which is characterized by a massive globular shape and radial structure, spicular tracts may represent a system to entrap and guide light toward the center of the sponge body. In such conditions, algal filaments develop in an environment otherwise prohibitive for autotrophic organisms. These data suggest that sponges could use spicules as a natural pipeline for light, a natural condition similar to modern fibre-optic systems.