Salhi N. auteur aut IRD Pagano Marc auteur aut IRD Felix C. auteur aut IRD Hafferssas A. auteur aut IRD Laadouze I. auteur aut IRD Laabir Mohamed auteur aut IRD Saidi N. auteur aut IRD text journalArticle eng text/pdf reformatted digital access 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. specialized Lepidodinium chlorophorum green tide environmental drivers MEDITERRANEE TUNISIE 036 034 13 10 1982 [24 ] 2025 https://www.documentation.ird.fr/hor/fdi:010095473 10.3390/jmse13101982 [F B010095473] https://www.documentation.ird.fr/hor/fdi:010095473 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2025-12/010095473.pdf IRD - Base Horizon / Pleins textes 2025-12-10 2026-01-29 fdi:010095473 fre