Characteristics of Fluorescence Spectra, UV Spectra, and Specific Growth Rates during the Outbreak of Toxic Microcystis Aeruginosa FACHB-905 and Non-Toxic FACHB-469 under Different Nutrient Conditions in a Eutrophic Microcosmic Simulation Device

Qi Wang,Wenjing Pang,Jun Li,Hengguo Yu,Xianfeng Huang,Shujie Ge,Chuanjun Dai,Min Zhao

doi:10.3390/w12082305

Abstract

Microcystis aeruginosa is the dominant alga forming cyanobacteria blooms, the growth of which is limited by available nutrients. Thus, it is necessary to study cyanobacteria blooms and explore the growth of Microcystis aeruginosa under different nutrient conditions. In this paper, we take Microcystis aeruginosa, including toxic Freshwater Algae Culture of Hydrobiology Collection (FACHB)-905 and non-toxic FACHB-469 strains, into account. The strains were cultured using a simulation device under different nutrient conditions. Ultraviolet spectra, three-dimensional fluorescence spectra, and kinetic parameter indicators of the two species are studied. Compared to FACHB-469, the results show that the specific growth rate of FACHB-905 is much higher, in particular, FACHB-905 is the dominant species under low nutrient conditions. Furthermore, the UV spectral characteristics indicate that the molecular weight of dissolved organic matter in the culture tank of toxic FACHB-905 is greater than that of FACHB-469. Additionally, the humification index of toxic FACHB-905 is slightly higher as well, which suggests that it is more stable in the presence of dissolved organic matter during blooms. Therefore, the toxic Microcystis strain is more likely to become the dominant species in water blooms under lower eutrophic conditions and water blooms formed by the toxic Microcystis strain may be more difficult to recover from.

Highlights

Cyanobacteria blooms have been reported frequently throughout the world over the past few decades [1,2]
The algal led to an increase in the condensation degree of organic matter in water bodies, where the condensation blooms led to an increase in the condensation degree of organic matter in water bodies, where the level of organic matter in Freshwater Algae Culture of Hydrobiology Collection (FACHB)-469 was higher than that of FACHB-905 in the same period
Condensation level of organic matter in FACHB-469 was higher than that of FACHB-905 in the same produced by FACHB-905 could be more stable in the bloom process, and the algal blooms of FACHB-905 period

Summary

Introduction

Cyanobacteria blooms have been reported frequently throughout the world over the past few decades [1,2]. Several of the world’s largest lakes, such as Lake Erie in the United States and Taihu Lake in China, have experienced algal blooms [3,4]. Cyanobacteria blooms are the most common type of algae blooms in China, including Microcystis, Anabaena, Aphanizomenon, and Planktothrix algae blooms. The frequency and area of Microcystis blooms are the highest, during which algae toxins are released. These toxins can negatively influence the surrounding ecosystems [5,6,7].

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