Plankton distribution and abundance in the Sundays River estuary, South Africa, with comments on potential feeding interactions

Three mysid and three calanoid copepod species dominated the mesozooplankton in the Sundays River estuary, South Africa. Mid estuary, there was considerable overlap in the spatial and temporal distribution of species. Mesozooplankton abundance was lowest during winter. Microzooplankton, consisting of ciliates, zooflagellates and rotifers, was most abundant in the middle of the estuary. Rotifer abundance was lowest in winter and autumn. Other microzooplankton showed no seasonal variation. Phytoplankton was dominated by micro- and nanoflagellates, dinoflagellates and euglenoids, but diatoms were very abundant after a flood. Chlorophyll a concentrations were greatest in the middle and upper estuary, but there they showed no seasonal fluctuations.