Using Different Response of Freshwater Algal Biomass to Limnological Parameters to Improve Harmful Algal Bloom Early Warning Strategies

Abstract

Harmful algal bloom (HAB) is a type of disastrous phenomenon taking place across the globe caused by certain overgrowing phytoplankton species that break the ecological balance in waterbodies. Early warning is a crucial step within the whole picture of HAB management, yet given that HAB can be caused by different algal species due to their distinctive optimal reproduction environment, few studies and policies have scrutinized such differences, leaving current early warning mechanisms less comprehensive. Based on 15 global long-term freshwater monitoring datasets, this study examines the relationship between algal population and major limnological parameters including total nitrogen, total phosphorus, nitrogen: phosphorous ratio, and water temperature. Results have indicated genera and species under the division Bacillariophyta and Cyanophyta are the most commonly observed alga across all lakes. Based on the locally weighted scatterplot smoothing technique (LOWESS) techniques, the paper has also found significant differences between division, genus, and species of dominant alga in terms of all four aforementioned limnological parameters. To enhance future HAB early warning mechanisms, management personnel and policy makers should focus on enhancing the taxonomic specificity of biomass monitoring and nitrogen: phosphorous measurement. Additionally, management efforts of each lake should be spent on the lakes’ unique dominant alga with significant differences along their taxonomic hierarchies.