Phytoplankton composition of the tidal cycle in the Bahía Blanca Estuary (Argentina)

This dataset contains phytoplankton taxonomic composition and abundance data collected during a semidiurnal tidal cycle in the Bahía Blanca Estuary (Argentina). Surface water samples were collected using a Van Dorn bottle at discrete time points across different tidal phases (high tide, flood, ebb, and low tide). Samples were preserved with Lugol's solution and analyzed using a 1 mL Sedgwick–Rafter counting chamber under an upright light microscope (Leica DM500). Taxa were identified to the lowest possible taxonomic level. The dataset characterizes short-term variability in phytoplankton community structure under tidally driven conditions.