Effects of copper and butyltin compounds on the growth, photosynthetic activity and toxin production of two HAB dinoflagellates : the planktonic Alexandrium catenella and the benthic Ostreopsis cf. ovata
|Author(s)||Couet Douglas1, 2, Pringault Olivier1, Bancon-Montigny Chrystelle3, Briant Nicolas4, Poulichet Francoise Elbaz3, Delpoux Sophie3, Yahia Ons Kefi-Daly2, Hela Bengharbia2, Charaf M'Rabet2, Herve Fabienne4, Rovillon Georges-Augustin4, Amzil Zouher4, Laabir Mohamed1|
|Affiliation(s)||1 : Montpellier Univ, CNRS, IFREMER,IRD, Ctr Marine Biodivers Exploitat & Conservat MARBEC, Pl Eugene Bataillon, F-34095 Montpellier, France.
2 : IRESA Carthage Univ, Tunisian Natl Inst Agron INAT, Res Grp Oceanog & Plankton Ecol, 43 Ave Charles Nicolle, Tunis 1082, Tunisia.
3 : Univ Montpellier, CNRS, Hydrosci Montpellier, IRD, Montpellier, France.
4 : IFREMER, Phycotoxins Lab, BP 21105, F-44311 Nantes, France.
|Source||Aquatic Toxicology (0166-445X) (Elsevier Science Bv), 2018-03 , Vol. 196 , P. 154-167|
|WOS© Times Cited||20|
|Keyword(s)||Alexandrium catenella, Ostreopsis cf. ovata, Cu, Butyltin, Photosynthesis, Toxins|
Controlled laboratory experiments were conducted to test the effects of copper (Cu2+) and butyltins (BuT) on the growth, photosynthetic activity and toxin content of two HABs (Harmful Algal Blooms) dinoflagellates, the planktonic Alexandrium catenella and the benthic Ostreopsis cf. ovata. Microalgae were exposed to increasing concentrations of Cu2+ (10−4 to 31 nM) or BuT (0.084 to 84 nM) for seven days. When considering the growth, EC50 values were 0.16 (±0.09) nM and 0.03 (±0.02) nM of Cu2+ for A. catenella and O. cf. ovata, respectively. Regarding BuT, EC50 was 14.2 (±6) nM for O. cf. ovata, while A. catenella growth inhibition appeared at BuT concentrations ≥27 nM. Photosynthetic activity of the studied dinoflagellates decreased with increasing Cu and BuT concentrations. For O. cf. ovata, the response of this physiological parameter to contamination was less sensitive than the biomass. Cu exposure induced the formation of temporary cysts in both organisms that could resist adverse conditions. The ovatoxin-a and -b concentrations in O. cf. ovata cells increased significantly in the presence of Cu. Altogether, the results suggest a better tolerance of the planktonic A. catenella to Cu and BuT. This could result in a differentiated selection pressure exerted by these metals on phytoplankton species in highly polluted waters. The over-production of toxins in response to Cu stress could pose supplementary health and socio-economic threats in the contaminated marine ecosystems where HABs develop.