The blooms of Alexandrium catenella are a long-outstanding issue in the world,causing severe impacts on the local marine environment and the aquaculture industry.Our previous studies have also shown that mango peel ex...The blooms of Alexandrium catenella are a long-outstanding issue in the world,causing severe impacts on the local marine environment and the aquaculture industry.Our previous studies have also shown that mango peel extracts(MPE)could effectively inhibit the growth of A.catenella under controlled laboratory conditions.However,it remains unknown whether using MPE to control A.catenella-induced harmful algal blooms(HABs)in aquaculture environments will cause the release of intracellular phycotoxins into the surrounding environment,potentially affecting aquatic organisms.Additionally,the potential impact of MPE itself on aquatic life is another concern.The objective of this study was to clarify these issues primarily by assessing the ecological safety of MPE.The intracellular and extracellular paralytic shellfish toxins(PSTs)contents of A.catenella was measured throughout the experimental period using liquid chromatography tandem time-of-flight mass spectrometry(LC-TOFMS).The results showed that MPE reduced the PSTs contents in A.catenella,while no significant fluctuation was observed in the extracellular PSTs contents.Meanwhile,MPE exhibited varying degrees of inhibitory effects on the four HABs species selected in this study but promoted the growth of three of the four bait algae.The recorded results regarding the survival rate,water clearance rate,and growth rate of aquatic organism exposed to MPE showed no significant different between the control group and the experimental group.This study clarified that using MPE to govern HABs in aquaculture environments would not affect the growth of cultured organisms and demonstrated that MPE has species-specific antialgal properties.These findings contribute to a better understanding of the potential of MPE as an algaecide.展开更多
Restraining algal growth by algaecide has been studied by many researchers, but the dosing time has not yet been studied. In this study, we examined the appropriate dosing time of algaecide through a series of experim...Restraining algal growth by algaecide has been studied by many researchers, but the dosing time has not yet been studied. In this study, we examined the appropriate dosing time of algaecide through a series of experiments. In the experiments, the pH value of water is significantly affected by Microcystis aeruginosa, and the variation of the pH value is in favor of the growth of the alga. Therefore, using acid algaecide in the period with maximum pH values, i.e., the stable phase, would change the acidity-alkalinity of the water significantly, and would negatively affect algal growth. Acid algaecide does not eliminate the alga effectively if the acid algaecide is dosed in the logarithmic growth phase. Using acid algaecide in the decline phase after algal bloom not only is unfavorable for eliminating the alga, but also prolongs the decline phase, and even brings about next larger algal bloom.展开更多
Copper sulfate and other chelated or complex copper forms are commonly used to manage nuisance and noxious algae and invasive weeds through direct application to aquatic systems. Regulatory scrutiny and perceived non-...Copper sulfate and other chelated or complex copper forms are commonly used to manage nuisance and noxious algae and invasive weeds through direct application to aquatic systems. Regulatory scrutiny and perceived non-target species impacts supported the need for an accurate risk assessment of fate and effects of copper applied as a pesticide. Copper inputs to aquatic systems originate from numerous sources (e.g. natural, storm water, industrial) whereas direct pesticide applications account for approximately 13%. Following a pesticide application, copper rapidly partitions to suspended algae and particulates and the majority (>90%) of applied copper is transferred to sediments within 2 days. Copper subsequently shifts to less bioavailable forms and risks to non-target species are significantly decreased. Additionally, the copper that partitions to sediments is diluted through migration to greater sediments depths and accretion. Even when elevated sediment copper concentrations were measured following chronic applications or high treatment levels, no adverse effects to non-target species were observed with laboratory or field experiments. When used appropriately copper can be an effective tool for water resource managers with negligible environmental impact.展开更多
基金The National Natural Science Foundation of China under contract No.42030402the program of Shanghai Subject Chief Scientist under contract No.23XD1401200the opening foundation of the Observation and Research Station of Bohai Strait Eco-Corridor,Ministry of Natural Resources under contract No.BH202405.
文摘The blooms of Alexandrium catenella are a long-outstanding issue in the world,causing severe impacts on the local marine environment and the aquaculture industry.Our previous studies have also shown that mango peel extracts(MPE)could effectively inhibit the growth of A.catenella under controlled laboratory conditions.However,it remains unknown whether using MPE to control A.catenella-induced harmful algal blooms(HABs)in aquaculture environments will cause the release of intracellular phycotoxins into the surrounding environment,potentially affecting aquatic organisms.Additionally,the potential impact of MPE itself on aquatic life is another concern.The objective of this study was to clarify these issues primarily by assessing the ecological safety of MPE.The intracellular and extracellular paralytic shellfish toxins(PSTs)contents of A.catenella was measured throughout the experimental period using liquid chromatography tandem time-of-flight mass spectrometry(LC-TOFMS).The results showed that MPE reduced the PSTs contents in A.catenella,while no significant fluctuation was observed in the extracellular PSTs contents.Meanwhile,MPE exhibited varying degrees of inhibitory effects on the four HABs species selected in this study but promoted the growth of three of the four bait algae.The recorded results regarding the survival rate,water clearance rate,and growth rate of aquatic organism exposed to MPE showed no significant different between the control group and the experimental group.This study clarified that using MPE to govern HABs in aquaculture environments would not affect the growth of cultured organisms and demonstrated that MPE has species-specific antialgal properties.These findings contribute to a better understanding of the potential of MPE as an algaecide.
基金supported by the Special Fund for Public Welfare Industry of Ministry of Water Resources of China(Grant No.200801001)National Science and Technology Major Projects of China(Grant No.2012ZX07506003-4)Central Public-interest Scientific Institution Basal Research Fund(Grants No.Y110002 and Y110005)
文摘Restraining algal growth by algaecide has been studied by many researchers, but the dosing time has not yet been studied. In this study, we examined the appropriate dosing time of algaecide through a series of experiments. In the experiments, the pH value of water is significantly affected by Microcystis aeruginosa, and the variation of the pH value is in favor of the growth of the alga. Therefore, using acid algaecide in the period with maximum pH values, i.e., the stable phase, would change the acidity-alkalinity of the water significantly, and would negatively affect algal growth. Acid algaecide does not eliminate the alga effectively if the acid algaecide is dosed in the logarithmic growth phase. Using acid algaecide in the decline phase after algal bloom not only is unfavorable for eliminating the alga, but also prolongs the decline phase, and even brings about next larger algal bloom.
文摘Copper sulfate and other chelated or complex copper forms are commonly used to manage nuisance and noxious algae and invasive weeds through direct application to aquatic systems. Regulatory scrutiny and perceived non-target species impacts supported the need for an accurate risk assessment of fate and effects of copper applied as a pesticide. Copper inputs to aquatic systems originate from numerous sources (e.g. natural, storm water, industrial) whereas direct pesticide applications account for approximately 13%. Following a pesticide application, copper rapidly partitions to suspended algae and particulates and the majority (>90%) of applied copper is transferred to sediments within 2 days. Copper subsequently shifts to less bioavailable forms and risks to non-target species are significantly decreased. Additionally, the copper that partitions to sediments is diluted through migration to greater sediments depths and accretion. Even when elevated sediment copper concentrations were measured following chronic applications or high treatment levels, no adverse effects to non-target species were observed with laboratory or field experiments. When used appropriately copper can be an effective tool for water resource managers with negligible environmental impact.
