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Aquat Toxicol

Title:		Effects of copper on the dinoflagellate Alexandrium minutum and its allelochemical potency
Author(s):		Long M; Holland A; Planquette H; Gonzalez Santana D; Whitby H; Soudant P; Sarthou G; Hegaret H; Jolley DF;
Address:		"School of Chemistry, University of Wollongong, NSW, 2522, Australia; Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539 CNRS UBO IRD IFREMER -Institut Universitaire Europeen de la Mer, Technopole Brest-Iroise, Rue Dumont d'Urville, 29280, Plouzane, France. Electronic address: marc.florian.long@gmail.com. La Trobe University, School of Life Science, Department of Ecology, Environment and Evolution, Centre for Freshwater Ecosystems, Albury/Wodonga Campus, VIC, Australia. Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539 CNRS UBO IRD IFREMER -Institut Universitaire Europeen de la Mer, Technopole Brest-Iroise, Rue Dumont d'Urville, 29280, Plouzane, France. School of Chemistry, University of Wollongong, NSW, 2522, Australia"
Journal Title:		Aquat Toxicol
Year:		2019
Volume:		20190308
Issue:
Page Number:		251 - 261
DOI:		10.1016/j.aquatox.2019.03.006
ISSN/ISBN:		1879-1514 (Electronic) 0166-445X (Linking)
Abstract:		"The dinoflagellate Alexandrium minutum produces toxic compounds, including paralytic shellfish toxins, but also some unknown extracellular toxins. Although copper (Cu) is an essential element, it can impair microalgal physiology and increase their toxic potency. This study investigated the effect of different concentrations of dissolved Cu (7 nM, 79 nM and 164 nM) on A. minutum allelochemical potency, here defined as negative effects of a protist on competing protists through the release of chemicals. This was studied in relation to its physiology. The effects of Cu were assessed on A. minutum growth, reactive oxygen species level, photosynthesis proxies, lipid metabolism, exudation of dissolved organic compounds, allelochemical potency and on the associate free bacterial community of A. minutum. Only the highest Cu exposure (164 nM) inhibited and delayed the growth of A. minutum, and only in this treatment did the allelochemical potency significantly increase, when the dissolved Cu concentration was still toxic. Within the first 7 days of the high Cu treatment, the physiology of A. minutum was severely impaired with decreased growth and photosynthesis, and increased stress responses and free bacterial density per algal cell. After 15 days, A. minutum partially recovered from Cu stress as highlighted by the growth rate, reactive oxygen species level and photosystem II yields. This recovery could be attributed to the apparent decrease in background dissolved Cu concentration to a non-toxic level, suggesting that the release of exudates may have partially decreased the bioavailable Cu fraction. Overall, A. minutum appeared quite tolerant to Cu, and this work suggests that the modifications in the physiology and in the exudates help the algae to cope with Cu exposure. Moreover, this study shows the complex interplay between abiotic and biotic factors that can influence the dynamic of A. minutum blooms. Modulation in allelochemical potency of A. minutum by Cu may have ecological implications with an increased competitiveness of this species in environments contaminated with Cu"
Keywords:		"Copper/*toxicity Dinoflagellida/*drug effects/metabolism/microbiology Marine Toxins/metabolism Microalgae/*drug effects/metabolism Microbiota/drug effects Pheromones/*metabolism Photosynthesis/drug effects Water Pollutants, Chemical/*toxicity Alexandrium;"
Notes:		"MedlineLong, Marc Holland, Aleicia Planquette, Helene Gonzalez Santana, David Whitby, Hannah Soudant, Philippe Sarthou, Geraldine Hegaret, Helene Jolley, Dianne F eng Netherlands 2019/03/18 Aquat Toxicol. 2019 May; 210:251-261. doi: 10.1016/j.aquatox.2019.03.006. Epub 2019 Mar 8"