Dominance and Growth Factors of Pseudanabaena sp. in Drinking Water Source Reservoirs, Southern China

Jingsi Gao,Jia Zhu,Wenyi Dong,Maowei Wang

doi:10.3390/su10113936

Abstract

Pseudanabaena sp. is a common and harmful species in freshwater cyanobacteria blooms. There are very few studies on its distribution characteristics and growth influencing factors. In the current study, it was found to be dominant in three cascading reservoirs in Southern China. Field observations and laboratory experiments were integrated to investigate the dominance and growth factors of Pseudanabaena sp. The effects of temperature, light intensity, nutrients, chemical oxygen demand (COD), pH, and disturbance on Pseudanabaena sp. growth were evaluated. The results indicated that Pseudanabaena sp. had significant positive correlations with water temperature, pH, and COD (p < 0.01) and a positive correlation with NH3-N (p < 0.05). The optimum growth temperature range for Pseudanabaena sp. was from 20 to 30 °C; hence, it usually has outbreaks in May and August. The optimum light intensity and pH for Pseudanabaena sp. were 27 μmol photons m−2s−1 and from 7 to 9, respectively. The superior tolerance for low light, disturbance, and phosphorus deficiency of Pseudanabaena sp. may be the main factors affecting its dominance in reservoirs. Controlling nitrogen was more effective than controlling phosphorus to avoid the risk that was brought by Pseudanabaena sp. This study contributed to the theoretical knowledge for the prediction and control of the growth of Pseudanabaena sp.

Highlights

Water, especially drinking water safety is an important guarantee for the realization of sustainable economic and social development
Seasonal cyanobacteria outbreaks in drinking water sources have become a severe issue around the world and have drawn considerable attention in recent years [1,2,3]
The cascading reservoirs monitored in this study are located in Southern China

Summary

Introduction

Especially drinking water safety is an important guarantee for the realization of sustainable economic and social development. Seasonal cyanobacteria outbreaks in drinking water sources have become a severe issue around the world and have drawn considerable attention in recent years [1,2,3]. Proliferating cyanobacteria are one of the most significant causes of source water deterioration [4,5] and are a serious threat to the drinking water treatment processes as they can plug the filtration tanks/membranes and produce cyanobacteria organic matters [1,6,7]. Cyanobacteria organic matters, including microcystins, taste and odor compounds, and precursors of disinfection by-products, have been reported to be difficult to fully remove by conventional drinking water treatment [8,9]. Cyanobacteria usually dominate phytoplankton communities in eutrophic drinking water sources worldwide [5,10,11], and Pseudanabaena sp. Several reports illuminated that besides producing MIB, Pseudanabaena sp. could produce cyanotoxins, including hepatotoxins and neurotoxins [13,17,21,22,23]

Methods

Results

Conclusion