| Calcareous skeletons of the coralline alga Hydrolithon onkodes are colonised by a variety of microboring organisms including euendolithic algae. The species composition of microboring organisms as well as the boring patterns and the boring activity differ between live and dead coralline crusts. The microborers inhabiting the live crusts form an obvious, macroscopically visible green layer in the basal part of the crust, which is in contact with the substratum underneath. Some species, primarily Plectonema terebrans (83 %) and Ostreobium quekettii (7 %) grow from the inside towards the crust's surface and produce a dense network of branched filaments. Following the death of the coralline alga, the skeletons are colonised at the surface and bored inward by... |
