Gastropod shells recycled – an example from a rocky tidal flat in the northern Red Sea

Gastropod recycling at a rocky intertidal flat in the Northern Bay of Safaga (Red Sea, Egypt) is a process of increasing encrustation, changing secondary inhabitants, and probably decreasing shell strength. Encrustation by coralline red algaestarts in the living gastropods, with the aperture area staying free of epigrowth. The dead gastropod shellsare colonized by hermit crabs, tend to be more heavily encrusted and show encrustation of the aperture. This justifies the description ‘pagurized’ and the conclusion that coralline red algaeproduce the same pagurization features as predominantly suspension-feeding invertebrates. After the shells are abandoned by inhabitants that carry them around, further growth of coralline algaeleads to rhodoliths, which are sometimes colonized by stomatopods. Secondary inhabitants therefore influence not only the taphocoenoses of gastropods but also the formation of rhodoliths.