Dominance and succession of Microcystis genotypes and morphotypes in Lake Taihu, a large and shallow freshwater lake in China. (December 2016)

• Record Type: Journal Article
• Authors: Liu, Yang; Xu, Yao; Wang, Zhongjie; Xiao, Peng; Yu, Gongliang; Wang, Guoxiang; Li, Renhui
• Is Part Of: Environmental pollution. Volume 219(2016)
• Page Start: 399
• Page End: 408
• Publication Date: 2016-12
• Subjects: Cyanobacterial blooms -- Genotype -- ITS -- Microcystis -- Morphotype -- Lake Taihu; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2016.05.021
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Lake Taihu, which is the third largest freshwater lake in China, has experienced extensive cyanobacterial ( Microcystis spp.) blooms over the past two decades. However, the distribution, dynamics and succession of the blooms have not been fully studied. To better understand the basic characteristics of Microcystis blooms in Lake Taihu, samples were collected from December 2008 to December 2009. The distribution and dynamics of different Microcystis morphotypes were characterized. Microcystis genotypes were analyzed also by sequencing the clone library of the internal transcribed spacer of the rRNA operon (ITS). The abundance of total Microcystis and the proportion of microcystin-producing subpopulation were estimated by using a quantitative PCR assay. Marked succession in both morphotypes and genotypes of the Microcystis population occurred during the course of the Microcystis bloom. The 2337 ITS sequences were obtained and were revealed to contain 618 Microcystis genotypes, which was the highest Microcystis genetic diversity reported in Lake Taihu. The T1 genotype, which was characterized by strains of Microcystis flos-aquae, was the most dominant genotype during winter and spring around the entire lake and likely acted as the main inoculum for forming blooms the following year. Water temperature periodically affected the succession of both Microcystis genotypes and morphotypes, whereas the micro-environment influenced the spatial distribution of Microcystis genotypes and morphotypes. High ratios of mcyD containing Microcystis subpopulations were detected during the onset and later bloom phases. A redundancy analysis (RDA) indicated that the water temperature and PO4 -P were the major factors controlling both the total Microcystis abundance and the proportion of microcystin-producing Microcystis in hyper-eutrophic waters. Graphical abstract: Highlights: The marked succession in both morphotype and genotype occurred during blooms. The T1 genotype, belonging to Microcystis flos-aquae, was the dominant genotype. High proportions of Microcystis containing mcyD were observed. Temperature and PO4 -P are the main environmental parameters. Abstract : A succession of Microcystis morphotypes and genotypes was demonstrated during bloom development in Lake Taihu.