Cumulative Effects of Physical, Chemical, and Biological Measures on Algae Growth Inhibition

Hao Li,Baiheng Yang,Lin Yang,Jiaqi Wang,Yanan Shao,Enze Zhang,Yi Tan,Ting Gao

doi:10.3390/w14060877

Abstract

Measures based on concurrent alterations of an environment’s physical, chemical, and biological factors are commonly adopted to control harmful algal blooms (HABs). It was postulated that the combinations and interactions of multiple measures could exert cumulative effects (as the overall effect may or may not be equal to the additive sum for each measure individually). However, few studies have further assessed whether the cumulative effect is synergistic, additive, or antagonistic. This study proposed a framework to distinguish and quantify the cumulative effects. We also designed an experiment to investigate the cumulative effect of the combined utilization of physical (flow velocity), chemical (copper), and biological (propionamide) measures on algae growth inhibition. The results show that the cumulative effect of physical and chemical measures on algae growth inhibition was antagonistic; the cumulative effect of physical and biological measures was antagonistic; the cumulative effect of chemical and biological measures was synergistic, and the cumulative effect of all the measures together tended to be antagonistic. These results showed that the synergistic interactions between chemical and biological measures produced antagonistic effects when physical measures were added. Through response surface methodology analysis, we also found that the physical factor was the most significant factor affecting the cumulative effect, followed by the chemical factor and then the biological factor. Our results provide a more detailed understanding of the interaction patterns among multiple measures that affect algal growth. Importantly, this understanding can be further integrated into future strategy development to fully exploit the potential of the cumulative effect at its maximum performance.

Highlights

Harmful algae blooms (HABs) have become a prevalent environmental issue in freshwater ecosystems because they increase anthropogenic eutrophication and produce other deleterious effects on the natural environment [1]
The results revealed that the cumulative effect of the combination of physical and chemical measures has an antagonistic effect on the regulation of algae growth
The results showed that the antagonistic effect between the two measures increased The results velocity, showed that the antagonistic effect between twonot measures with the flow indicating that the cumulative effectthe was constantincreased but influ6 of 15 with the flow velocity, indicating that the cumulative effect was not constant but influenced both flow velocity and copper concentration

Summary

Introduction

Harmful algae blooms (HABs) have become a prevalent environmental issue in freshwater ecosystems because they increase anthropogenic eutrophication and produce other deleterious effects on the natural environment [1]. The overgrowth of harmful algae can over-consume dissolved oxygen and nutrients that other aquatic organisms heavily rely on [2]. Harmful algae can provide multiple secondary metabolites [5]. Some secondary metabolites can cause taste and odor pollution, directly degrade the recreational function of surrounding water bodies, and pose a severe risk to drinking-water supply [6,7]. The negative impacts can be even more severe when the algae are toxic and produce algal toxins [8]. Since algae have an essential ecological role in aquatic ecosystems and many other natural systems, the more frequent and severe presence of HABs can have a catastrophic effect on environmental safety and human well-being [10]

Methods

Results

Discussion

Conclusion