Structure and dynamics of phytoplankton populations in the Black Sea from 2014 to 2017

This study investigated the seasonal variations in phytoplankton communities along the Turkish Black Sea coast (2014-2017). Analyzing data from 20 stations revealed high biodiversity (175 species across 14 classes). Phytoplankton abundance showed distinct seasonality, with a peak in summer (2017, 96.6%) and lows in winter, characterized by dinoflagellate dominance. In terms of biomass, diatoms dominated in half of the sampling seasons, while dinoflagellates dominated in the other half at the surface during 2014-2017. The dominance of dinoflagellates corresponded to the winters and summers of 2015 and 2016. The winter conditions of 2015 were harsh. The surface water community composition sometimes varied from that of the water column. Importantly, 44 potentially toxic species were identified, comprising 25% of the community and significantly contributing to both abundance (73.2-98.6%) and biomass (64-90.2%) throughout the year. These results highlight the unique structure of the Black Se..., The research carried out under the \"National Integrated Marine Pollution Monitoring Program\" was performed at 20 stations selected from 16 coastal water bodies (CWB) identified along the entire Black Sea coast of Türkiye from the westernmost İğneada (Bulgarian border) to the easternmost Hopa (Georgian border) between 2014 and 2017. Six cruises (2014: Summer, 2015: Winter and Summer, 2016: Winter and Summer and 2017: Summer) were implemented in the study area with R/V TÜBİTAK MARMARA., , # Data from: Structure and dynamics of phytoplankton populations in the Black Sea from 2014 to 2017

[https://doi.org/10.5061/dryad.fqz612k0n](https://doi.org/10.5061/dryad.fqz612k0n)

The research under the Turkish Integrated Marine Pollution Monitoring Program initiated in 2014 as part of the national program by the Ministry of Environment, Urbanization, and Climate Change and coordinated by TÜBİTAK Marmara Research Center was conducted at 20 stations selected from 16 coastal water bodies along the entire Black Sea coast of Turkey, from the westernmost İğneada to the easternmost Hopa (Georgian border), between 2014 and 2017 (Fig. 1). Six cruises (August/Summer 2014; January/Winter and August/Summer 2015; January/Winter and August/Summer 2016; and August/Summer 2017) were implemented in the study area with R/V TÜBİTAK Marmara. The details of the stations in the study area are provided in Supplementary Material Table S1 of the associated manuscript.

## Description of the data and file ...,