Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Journal of Marine Science and Engineering 1982 [24 ] Lepidodinium chlorophorum green tide environmental drivers MEDITERRANEE TUNISIE 2025 fdi:010095473 ENG Journal of Marine Science and Engineering ISI:001603806700001 10 10.3390/jmse13101982 https://www.documentation.ird.fr/hor/fdi:010095473 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2025-12/010095473.pdf 13 Horizon (IRD) 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. 036 ; 034 UR235 / UR248 Algérie / Tunisie