Ultrastructural evidence of bacterial damage to Spongia officinalis fibres (Porifera, Demospongiae)

Skeletons of healthy and damaged specimens of Spongia officinalis were examined by scanning and transmission electron microscopy. Comparisons of the fibre net demonstrated that bacterial invasion was responsible for the decay of spongin fibres in affected sponges. Bacteria were located both inside and on the surface of fibres. Irregularly shaped spaces and canals together with many orifices were visible scattered over the fibre surfaces. Tissue reparation consisted of isolation of affected areas and permitted complete recovery and regeneration of many specimens.