Spring Diatom Blooming Phases in a Representative Eutrophic Bay of the Three-Gorges Reservoir, China

Abstract

ABSTRACT We investigated dynamics of the phytoplankton community and abiotic factors in Xiangxi Bay of the Three-Gorge Reservoir, China, by daily sampling a specific site during a spring algal bloom (February 23-April 28, 2005). Among the 76 taxa observed, Asterionella formosa and Cyclotella spp. were the dominants, accounting for 47.2% and 29.9% of the total abundance, respectively. We determined the five distinct developing phases of the bloom by analyzing the dissimilarity of physicochemical parameters. Simultaneously, six phytoplankton community groups were distinguished by TWINSPAN classifications. The pattern for algal community succession was similar to that for the bloom phase shift, and the structural complexity of communities significantly decreased over time. Water temperature and silicate were the main factors that related to the development of the bloom and the shifts of the phytoplankton community.