Temporal and spatial variability of plankton communities in a shallow embayment of the eastern Mediterranean  <B>Temporal and spatial variability of plankton communities in a shallow embayment of the eastern Mediterranean</B><P><B>Epaminondas D. Christou, Kalliopi Pagou, <BR> Savvas Christianidis & Evangelos Papathanassiou</B><I><P> National Centre for Marine Research, GR-16604 Hellenikon, Athens, Greece</I><B><P> Abstract</B><BR> Plankton abundance and composition were studied during 1991 and 1992 in the Maliakos Gulf, Greece, a shallow (maximum depth <27 m) semi-enclosed embayment located in the north-western part of North Evoikos. It receives large amounts of fresh water through the Sperchios river, especially during winter, as well as domestic and industrial effluents. Phytoplankton and zooplankton abundances were generally lower than expected when compared to other similar areas. In general, the variations of plankton abundance and composition were attributed to water circulation and movements and, to a lesser extent, topography and anthropogenic influences. The results of the study indicated that turbidity affects zooplankton abundance and distribution. In addition, the tolerance of the dominant copepods <I>Acartia clausi</I> and <I>Oithona helgolandica</I> to environmental disturbances is questioned. The role of food as a limiting factor for zooplankton growth is also discussed. It is suggested that, in the study area there are periods with a weak autotrophic pathway where the heterotrophic pathway is expected to play an important role in the energy flux.<I><P> Keywords</I>: phytoplankton, zooplankton, shallow, temporal and spatial distribution, eastern Mediterranean.<P>