The dynamics of some ecological factors controlling abundance and structure of plankton community were studied at small scales of time and space in Boughaz El-Maadiya, a channel connecting a coastal lake (Lake Edku) with the Egyptian Mediterranean water at Abu Kir Bay. The continuous mixing of sea and lake waters led to instability in the ecological
conditions and the biological structure of the ecosystem in the area, particularly the plankton.
Weekly records ecological parameters and plankton abundance from the end of April to end of October 1997 revealed marked variations. Temperature of the surface water followed the traditional seasonal variations known in the Egyptian coastal waters, ranging from 19 to 290C. The pH experienced relatively wide temporal and spatial changes fluctuating
between 7.51 and 8.85. The water transparency appeared mostly low, reflected by small secchi depths (40-100 cm) during the whole period of study. Dissolved oxygen varied between 1.9 and 5.9 mi/I. Surface salinity fluctuated between a minimum of 0.84% and a maximum of 35.69 %O Phytoplankton crop measured by chlorophyll a sustained mostly high
concentrations (10.6-124.7 mg/m3), which might indicate an advanced eutrophication of the study area. Zooplankton counts were mostly high (average 86,473 organisms/m3) varying between 9x103=415x103 organisms/m3. Both phyto- and zooplankton crops showed remarkable spacial and temporal variations.
Statistical treatment of the results indicated significant correlations between different parameters.