First record of Lepidodinium chlorophorum and the associated phytoplankton community responsible of the green tide south Western Mediterranean Sea (Hammam-Lif, Tunisia) Salhi, N. /Pagano, Marc Felix, C. Hafferssas, A. Laadouze, I. /Laabir, Mohamed Saidi, N. Lepidodinium chlorophorum green tide environmental drivers The bloom-forming dinoflagellates and euglenophyceae were observed in the coastal waters of Hammam-Lif (Southern Mediterranean), during a green tide event on 3 June 2023. The bloom was dominated by Lepidodinium chlorophorum, identified through ribotyping with densities reaching 2.3 x 10(7) cells<middle dot>L-1. Euglena spp. and Eutrepsiella spp. contributed to the discoloration, with abundances up to 2.9 x 10(7) cells<middle dot>L-1. Environmental data revealed significant depletion of nitrite and nitrate, coinciding with a rapid increase in sunlight duration, likely promoting the proliferation of L. chlorophorum and euglenophyceae. By 5 June, two days after the bloom, nutrient stocks were exhausted. Diatoms appeared limited by low silicate concentrations (<0.05 <mu>mol<middle dot>L-1), while dissolved inorganic phosphate and Nitrogen-ammonia were elevated during the bloom (0.88 and 4.8 mu mol<middle dot>L-1, respectively), then decreased significantly afterward (0.23 and 1.06 mu mol<middle dot>L-1, respectively). Low salinity (34.0) indicated substantial freshwater input from the Meliane River, likely contributing to nutrient enrichment and bloom initiation. After the event, phytoplankton abundance and chlorophyll levels declined, with a shift from dinoflagellates to diatoms. The accumulation of pigments (chlorophyll b and carotenoids) and the presence of Mycosporine-like amino acids (MAAs) during and after the bloom suggest that UV radiation and Nitrogen-ammonia were key drivers of this green tide. 2025 text https://www.documentation.ird.fr/hor/fdi:010095473 fdi:010095473 Salhi N., Pagano Marc, Felix C., Hafferssas A., Laadouze I., Laabir Mohamed, Saidi N.. First record of Lepidodinium chlorophorum and the associated phytoplankton community responsible of the green tide south Western Mediterranean Sea (Hammam-Lif, Tunisia). 2025, 13 (10), 1982 [24 ] EN MEDITERRANEE TUNISIE