Abstract Title

Potential role of sulphate in cylindrospermopsin dynamics within urban freshwaters

Start Date

26-5-2022 12:00 PM

End Date

26-5-2022 12:15 PM

Abstract

Cylindrospermopsin is a cyanotoxin that poses severe human health threats and is a major concern in freshwater systems around the world. It is mainly produced by Raphidiopsis sp., although pico-cyanobacteria have recently also been discovered to be causative. Urban freshwaters are especially vulnerable because due to human activity within its watershed that drives eutrophication and pollution. Understanding the urban drivers of cylindrospermopsin dynamics is crucial for managing these waters. We therefore sampled a tropical urban freshwater system at a bi-weekly interval over a year and at three-hour intervals over three days. Multivariate analyses from both sampling periods indicated poor correlation between Raphidiopsis sp. and cylindrospermopsin, but pico-cyanobacteria density correlated with cylindrospermopsin (p < 0.05; r2 = 0.16) over the one-year sampling. During the three-day sampling, pico-cyanobacteria densities were very low and not significantly correlated with cylindropermopsin. Across both sampling periods, nitrogen also provided a poor explanatory factor for the cylindrospermopsin patterns. However, sulphate was significant. Within eutrophic urban freshwaters, where macronutrients tend to be in excess, this study therefore suggests a need to focus instead on micronutrients such as sulphate which may be closely associated with pollution regimes. Such information is useful in identifying important targets for freshwater management efforts.

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May 26th, 12:00 PM May 26th, 12:15 PM

Potential role of sulphate in cylindrospermopsin dynamics within urban freshwaters

Cylindrospermopsin is a cyanotoxin that poses severe human health threats and is a major concern in freshwater systems around the world. It is mainly produced by Raphidiopsis sp., although pico-cyanobacteria have recently also been discovered to be causative. Urban freshwaters are especially vulnerable because due to human activity within its watershed that drives eutrophication and pollution. Understanding the urban drivers of cylindrospermopsin dynamics is crucial for managing these waters. We therefore sampled a tropical urban freshwater system at a bi-weekly interval over a year and at three-hour intervals over three days. Multivariate analyses from both sampling periods indicated poor correlation between Raphidiopsis sp. and cylindrospermopsin, but pico-cyanobacteria density correlated with cylindrospermopsin (p < 0.05; r2 = 0.16) over the one-year sampling. During the three-day sampling, pico-cyanobacteria densities were very low and not significantly correlated with cylindropermopsin. Across both sampling periods, nitrogen also provided a poor explanatory factor for the cylindrospermopsin patterns. However, sulphate was significant. Within eutrophic urban freshwaters, where macronutrients tend to be in excess, this study therefore suggests a need to focus instead on micronutrients such as sulphate which may be closely associated with pollution regimes. Such information is useful in identifying important targets for freshwater management efforts.