Effects of copper on the dinoflagellate Alexandrium minutum and its allelochemical potency

摘要: 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 potency. This study investigated the effect of different concentrations dissolved Cu (7 nM, 79 nM 164 nM) on A. allelochemical potency, here defined as negative effects a protist competing protists through release chemicals. was studied in relation to its physiology. were assessed growth, reactive oxygen species level, photosynthesis proxies, lipid metabolism, exudation organic potency associate free bacterial community minutum. Only highest exposure (164 nM) inhibited delayed growth minutum, only this treatment did significantly increase, when concentration still toxic. Within first 7 days high treatment, severely impaired with decreased photosynthesis, increased stress responses density per algal cell. After 15 days, partially recovered from highlighted by rate, level photosystem II yields. recovery could be attributed apparent decrease background non-toxic suggesting that exudates may have bioavailable fraction. Overall, appeared quite tolerant Cu, work suggests modifications help algae cope exposure. Moreover, shows complex interplay between abiotic biotic factors influence dynamic blooms. Modulation ecological implications competitiveness environments contaminated Cu.