Phytoplankton data series (1984–2020) from the LTER-MC site (LTER_EU_IT_061, Gulf of Naples, Mediterranean Sea)

The dataset contains a long-term time series of phytoplankton abundance data collected at the LTER-MC (MareChiara) site in the Gulf of Naples (Mediterranean Sea) from 1984 to 2020. The dataset includes species-level abundance records for 318 phytoplankton taxa derived from 1,341 out of 1,352 sampling events. For the remaining 11 sampling events, phytoplankton abundance data are reported as not available. Phytoplankton samples were collected from surface waters using Niskin bottles and analysed through light microscopy following the Utermöhl method. Abundance values are reported as cells ml⁻¹, providing a record of phytoplankton community composition and temporal variability over more than three decades. The dataset can support research on phytoplankton diversity, community dynamics, and long-term changes in marine plankton assemblages.