Couet Douglas, Pringault Olivier, Bancon-Montigny Chrystelle, Briant Nicolas, Elbaz Poulichet Françoise, Delpoux Sophie, Kefi-Daly Yahia Ons, Hela BenGharbia, Charaf M'Rabet, Hervé Fabienne, Rovillon Georges, Amzil Zouher, Laabir Mohamed
Center for Marine Biodiversity, Exploitation and Conservation (MARBEC): IRD, IFREMER, CNRS, Montpellier University, Montpellier, France; Research Group on Oceanography and Plankton Ecology, Tunisian National Institute of Agronomy (INAT), IRESA-Carthage University, 43 Avenue Charles Nicolle, Tunis 1082, Tunisia.
Center for Marine Biodiversity, Exploitation and Conservation (MARBEC): IRD, IFREMER, CNRS, Montpellier University, Montpellier, France.
Aquat Toxicol. 2018 Mar;196:154-167. doi: 10.1016/j.aquatox.2018.01.005. Epub 2018 Jan 6.
Controlled laboratory experiments were conducted to test the effects of copper (Cu) 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 Cu (10 to 31 nM) or BuT (0.084 to 84 nM) for seven days. When considering the growth, EC values were 0.16 (±0.09) nM and 0.03 (±0.02) nM of Cu for A. catenella and O. cf. ovata, respectively. Regarding BuT, EC 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.
开展了对照实验室实验，以测试铜（Cu）和丁基锡（BuT）对两种有害藻华（HABs）甲藻（浮游的链状亚历山大藻和底栖的卵形仿石藻）生长、光合活性和毒素含量的影响。将微藻暴露于浓度不断增加的铜（10至31 nM）或丁基锡（0.084至84 nM）中7天。在考虑生长情况时，链状亚历山大藻和卵形仿石藻对铜的有效浓度（EC）值分别为0.16（±0.09）nM和0.03（±0.02）nM。对于丁基锡，卵形仿石藻的有效浓度为14.2（±6）nM，而当丁基锡浓度≥27 nM时，链状亚历山大藻的生长受到抑制。所研究甲藻的光合活性随铜和丁基锡浓度的增加而降低。对于卵形仿石藻，该生理参数对污染的响应不如生物量敏感。铜暴露诱导两种生物形成可抵抗不利条件的临时孢囊。在有铜存在的情况下，卵形仿石藻细胞中的卵毒素-a和-b浓度显著增加。总体而言，结果表明浮游的链状亚历山大藻对铜和丁基锡具有更好的耐受性。这可能导致这些金属对高污染水域中的浮游植物物种施加差异化的选择压力。在有害藻华爆发的受污染海洋生态系统中，因铜胁迫导致的毒素过量产生可能带来额外的健康和社会经济威胁。
