A multi-technique approach for the quantification of Microcystis aeruginosa FACHB-905 biomass during high algae-laden periods

Abstract

A pronounced dominance of toxic cyanobacteria has been found in eutrophic water bodies, with Microcystis being a common species. Although toxic cyanobacteria are commonly described worldwide, few recent papers on the sensitive and effective quantification of cyanobacteria have been published. In this paper, a multi-technique approach was applied by the use of cell density counting, cell viability testing, chlorophyll a determination, microcystin monitoring and gene extraction techniques to quantitatively analyse the cyanobacterial biomass of Microcystis aeruginosa FACHB-905. The entire dataset was used to examine the relationships between these indices. Results showed that, for 10⁷ viable cells in the experimental conditions, the contents of chlorophyll a, microcystin-LR and total genes (16S rDNA) averaged 2.65 μg, 0.61 μg and 0.79 μg, respectively. For different cell viability proportions in the same particular phase of growth, it is easy to obtain the respective amount of viable cells and inactive cells and their measurable indices when any one of the three indices, chlorophyll a, DNA or microcystin-LR, is measured. This study provides a new perspective and method for determining multiple indices of toxic cyanobacteria during the same conditions and phases.

Keywords:

• cyanobacteria quantification
• cell density
• cell viability
• chlorophyll a concentration
• microcystin production
• gene content

Acknowledgements

This work was supported by the International Science & Technology Cooperation Program of China (2010DFA91150), the International Cooperation Research of Shandong Province (2008GJHZ20601), the Shanghai Tongji Gao Tingyao Environmental Science & Technology Development Foundation and the Graduate Innovation Foundation of Shandong University (yyx10035). The authors thank Dr. Findlay Nicol for revising the English in the manuscript.