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Mitigating fish-killing Prymnesium parvum algal blooms in aquaculture ponds with clay: the importance of pH and clay type


Seger, A and Dorantes Aranda, JJ and Muller, MN and Body, A and Peristyy, A and Place, AR and Park, TG and Hallegraeff, G, Mitigating fish-killing Prymnesium parvum algal blooms in aquaculture ponds with clay: the importance of pH and clay type, Journal of Marine Science and Engineering, 3, (2) pp. 154-174. ISSN 2077-1312 (2015) [Refereed Article]

PDF (J. Mar. Sci. Eng. 2015, 3, 154-174; )

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© 2015 by the authors; licensee MDPI, Basel, Switzerland. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0)

DOI: doi:10.3390/jmse3020154


Clay minerals have previously been used to mitigate algal blooms because of their ability to flocculate algal cells or remove nutrients, but also offer considerable potential to remove ichthyotoxins. When a barramundi farm in tropical Australia suffered substantial fish mortalities due to a bloom of the ichthyotoxic haptophyte Prymnesium parvum, the farm manager decided to manipulate pond water N:P ratios through removal of phosphorus by the addition of lanthanum-modified bentonite clay (Phoslock™) to successfully mitigate ichthyotoxic effects. We conducted Prymnesium culture experiments under a range of N:P ratios, screening 14 different clays (two zeolites, four kaolins, six bentonites and two types of Korean loess) at pH 7 and 9 for cell flocculation and removal of ichthyotoxicity assessed with the RTgill-W1 cell line assay. Application of Phoslock™ to cultures grown at different N:P effectively removed 60%–100% of water-soluble toxicity of live Prymnesium (dependent on nutritional status). While most clays efficiently flocculated Prymnesium cells (≥80% removal), cell removal proved a poor predictor of ichthyotoxin adsorption. Extensive clay screening revealed that at elevated pH, as commonly associated with dense algal blooms, most clays either exacerbated ichthyotoxicity or exhibited significantly reduced toxin adsorption. Interpretation of changes in clay zeta potential at pH 7 and 9 provided valuable insight into clay/ichthyotoxin interactions, yet further research is required to completely understand the adsorption mechanisms. Bentonite-type clays proved best suited for ichthyotoxin removal purposes (100% removal at ecologically relevant pH 9) and offer great potential for on-farm emergency response.

Item Details

Item Type:Refereed Article
Keywords:Prymnesium parvum, mitigation, clay, pH, ichthyotoxicity, gill cell line assay, RTgill-W1, zeta potential, mitigating algal blooms
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Phycology (incl. marine grasses)
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - aquaculture
Objective Field:Fisheries - aquaculture not elsewhere classified
UTAS Author:Seger, A (Dr Andreas Seger)
UTAS Author:Dorantes Aranda, JJ (Dr Juan Dorantes Aranda)
UTAS Author:Peristyy, A (Dr Anton Peristyy)
UTAS Author:Hallegraeff, G (Professor Gustaaf Hallegraeff)
ID Code:101021
Year Published:2015
Funding Support:Australian Research Council (DP130102859)
Deposited By:IMAS Research and Education Centre
Deposited On:2015-06-07
Last Modified:2016-04-18
Downloads:429 View Download Statistics

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