Time behaviour of marine ciliated protozoa of sandy shores  <B>Time behaviour of marine ciliated protozoa of sandy shores</B><P><B>Pia Lucchesi & Giovanni Santangelo</B><I><P> Dipartimento Scienze Ambiente e Territorio, Università di Pisa, I-56126 Pisa, Italy</I><B><P> Abstract</B><BR> An interstitial ciliate community living in an exposed Mediterranean sandy shore was analysed over time. A total number of 134 sandy cores was collected and examined during the period 1988-1992. Two clear-cut seasonal trends were identified: a springsummer trend characterized by higher, stratified densities, and an autumnwinter trend in which densities decreased and distribution was more uniform. In the springsummer period the community was dominated by species of one or two genera, which tended to form polyspecific clumps. During this period, it was possible to analyse the ciliate community composition within the time interval between two storms, at which time some recolonization sequences were identified. Small ciliates, mainly <I>Strombidium</I> spp., were found in the early recolonization phases, while species of the genus <I>Diophrys</I>, together with bigger species of the genera <I>Condylostoma</I> and <I>Remanella</I> characterized the community during advanced recolonization phases.<BR> Principal component analysis, based on the taxonomic composition of samples, revealed two easily distinguishable ensembles, each corresponding to a seasonal period. The same method distinguished between samples collected during the springsummer periods of two different years characterized by different hydrodynamic conditions.<I><P> Keywords</I>: Ligurian Sea, shallow sandy bottoms, interstitial ciliates.<P>