Comparison of Functional Groups of Phytoplankton in FG, MFG, and MBFG: Taking Three Reservoirs as an Example in Guizhou Plateau

Abstract

Phytoplankton classification is the foundation for revealing the succession rules of phytoplankton communities and for conducting water ecology investigation. At present, the classification methods of functional group (FG), morpho-functional group (MFG), and morphology-based functional group (MBFG) are widely used, although great differences occur among the classification methods of different FGs. In order to compare the differences among FG, MFG and MBFG classification methods, FG classification and redundant analysis (RDA) were used to sample and analyze the phytoplankton community structures and the physical and chemical indicators of water environment in April 2017 (normal seasons) and August 2017 (wet seasons). The following results were noted. ①The MFG and FG had overlapping parts, whereas the MBFG was differed significantly from FG and MFG. ②The FG considers the physiological and ecological characteristics of phytoplankton, which can better explain the correlation with the environment and can accurately reflect the relationship between environmental factors and the phytoplankton niche. Moreover, the environmental factors and eutrophication status of the reservoir can be predicted according to the dominant FGs of phytoplankton; however, the FG needs to have systematic knowledge of phytoplankton identification and a large workload. The MFG classification method is simple and easily understood, which can better explain the relationship between phytoplankton and environmental factors; however, it is weakly connected with environmental factors. The MBFG classification method is the simplest and most efficient, although its interpretation degree to the environment is not sufficient. ③Each of the three classification methods has advantages and disadvantages; therefore, appropriate classification methods are selected according to different research purposes and their actual needs.