20.500.12556/DiRROS-30008 Copper toxicity as stressor in Chaetoceros calcitrans under different salinity levels: Growth inhibition, ROS accumulation, and alterations in fatty acid and PUA profiles The sensitivity of marine microalgae to metal contamination, particularly copper (Cu), is well recognized in ecotoxicology, providing key insights into predicting marine pollution impacts. This study examined the combined effects of Cu toxicity and salinity on the diatom Chaetoceros calcitrans under controlled laboratory conditions. Toxicity assays were conducted using two environmentally relevant Cu concentrations (2 and 5 μg L−1) and three salinity levels (33, 36, and 39) over 96 h, with cell responses analyzed via flow cytometry. Specific growth rate (SGR), chlorophyll fluorescence, fatty acid methyl ester (FAME) composition, polyunsaturated aldehydes (PUAs), and reactive oxygen species (ROS) production were evaluated. Results showed that SGR increased from 1.7 d−1 at salinity 33 to 1.9 d−1 at 39, indicating enhanced growth at higher salinity. However, Cu exposure significantly reduced SGR, particularly under 5 μg L−1 Cu at salinity 33, where SGR dropped to 0.86 d−1. ROS levels were highest under the combined low salinity (33) and 5 μg L−1 Cu treatment, suggesting strong oxidative stress. PUA profiles shifted with Cu and salinity, with stress-related compounds such as 2E,4E/Z-decadienal and 2E,4E/Z,7Z-decatrienal increasing at low salinity. Fatty acid analysis revealed marked rises in saturated fatty acids, especially palmitic acid (C16:0) and myristic acid (C14:0), under Cu exposure. In the Cu2/39 treatment, C16:0 reached 1.34 × 104 fmol cell−1 compared to 1.36 × 103 fmol cell−1 in the control. Monounsaturated fatty acids, notably palmitoleic acid (C16:1), also increased, reaching 7. 46 × 103 fmol cell−1 versus 1.71 × 103 fmol cell−1 in the control. Conversely, polyunsaturated fatty acids, including arachidonic acid (C20:4) and eicosapentaenoic acid (C20:5 n-3), decreased significantly following Cu exposure. Overall, elevated salinity mitigated Cu-induced growth inhibition but intensified oxidative and biochemical stress, underscoring the complex, endpoint-specific responses of C. calcitrans to multiple environmental stressors. climate change ecotoxicology marine diatom flow cytometry lipids podnebne spremembe ekotoksikologija morske diatomeje pretočna citometrija lipidi true false true Angleški jezik Slovenski jezik Neznano 2026-06-11 12:38:37 2026-06-11 12:38:37 2026-06-12 03:54:43 0000-00-00 00:00:00 2026 0 0 Nasl. z nasl. zaslona; Soavtorji: Juan Rodríguez-Márquez, María Úbeda-Manzanaro, Marta Sendra, Ignacio Moreno-Garrido, Ana Bartual, María J. Ortega; Opis vira z dne 26. 5. 2026; str. 1-12 Vol. 394, [article no.] 144790 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2026-02-01 504.5:574.64 1879-1298 10.1016/j.chemosphere.2025.144790 279445507 https://www.sciencedirect.com/science/article/pii/S0045653525007386?via%3Dihub 1 b55ac461-6581-11f1-9215-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=45220 RAZ_Kholssi_Rajaa_2026.pdf RAZ_Kholssi_Rajaa_2026.pdf 1 10DDBA8D596C4DB70214B841257C24B6 a3f6d28fc29f28470c0497cb2f7e8e8666d2486b11e148050ba645b3198a9ca4 d9af2f40-6581-11f1-9215-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=45221 Nacionalni inštitut za biologijo 0 0 0