Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4528897 | Aquatic Toxicology | 2016 | 9 Pages |
•An inhibitory effect of three toxic PUAs for Ostreopsis cf. ovata growth was shown.•Longer-chain PUAs had a higher inhibitory effect than shorter-chain ones.•At the highest concentrations of decadienal up to 79% of abnormal cells were observed.•A DNA degradation and an increase of lipid droplets occurred with all tested PUAs.
Diatoms have been shown to produce and release a wide range of secondary metabolites that mediate interactions between individuals of different species. Among these compounds, different types of fatty acid derived long-chained polyunsaturated aldehydes (PUAs) have been related to multiple functions such as intra- or interspecific signals and adverse effect on the reproduction of marine organisms. Several studies have reported changes on growth, cell membrane permeability, flow cytometric properties and cell morphology in phytoplankton organisms exposed to PUAs, but little information is available on the effect of these compounds on benthic microalgae. Ostreopsis cf. ovata is a toxic benthic dinoflagellate which causes massive blooms along the Mediterranean coasts typically during the late summer period. In this study the effects of three toxic PUAs known to be produced by several algae (2E,4E-decadienal, 2E,4E-octadienal and 2E,4E-heptadienal) on the growth, cytological features and cell morphology of O. cf. ovata were investigated. Our results show a clear decrease of O. cf. ovata growth with longer-chain molecules than with shorter-chain ones, confirmed also by EC50 values calculated at 48 h for 2E,4E-decadienal and 2E,4E-octadienal (6.6 ± 1.5, 17.9 ± 2.6 μmol L−1 respectively) and at 72 h for 2E,4E-heptadienal (18.4 ± 0.7 μmol L−1). Moreover, morphological analysis highlighted up to 79% of abnormal forms of O. cf. ovata at the highest concentrations of 2E,4E-decadienal tested (9, 18 and 36 μmol L−1), a gradual DNA degradation and an increase of lipid droplets with all tested PUAs. Further studies are needed to better clarify the interactions between diatoms and O. cf. ovata, especially on bloom-forming dynamics.