title: Succession of phytoplankton assemblages in response to large-scale reservoir operation: a case study in a tributary of the Three Gorges Reservoir, China.
abstract: The Three Gorges Dam (TGD) has greatly altered ecological and environmental conditions within the reservoir region, but it is not known how these changes affect phytoplankton structure and dynamics. Here, a bimonthly monitoring program was implemented from 2007 to 2009 to study the impact of damming on phytoplankton assemblages in the backwater area of the Pengxi River (PBA). By application of the phytoplankton functional group (C strategists, competitive species; S strategists, stress-tolerant species; R strategists, rapid propagation species), seasonal changes in phytoplankton relative to environmental variations were evaluated using ordination analysis. Seasonal patterns of phytoplankton dynamics were detected during this study, with CS/S strategists causing algal blooms from mid-spring to early summer, CS/CR strategists often observed during flood season, and CS strategists dominant during mid-autumn. CR/R groups dominated during winter and caused algal blooms in February. Our results indicated that phytoplankton assemblages were directly related to reservoir operation effects. Generally, the TGD had a low water level during flood season, resulting in a relatively short hydraulic retention time and intensive variability, which supported the cooccurrence of CS and CR species. During the winter drought season, water storage in the TGD increased the water level and the hydraulic retention time in the PBA, enabling R/CR strategists to overcome the sedimentation effect and to out-compete S/CS species in winter. As expected, these diversity patterns were significantly correlated with the hydraulic retention time and nutrient limitation pattern in the PBA. This study provides strategic insight for evaluating the impacts of reservoir operations on phytoplankton adaptation.
authors: Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China.
authors: Yan
authors: Y
authors: Xiao
authors: Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China. lizhe@cigit.ac.cn.
authors: Zhe
authors: Z
authors: Li
authors: Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China.
authors: Jinsong
authors: J
authors: Guo
authors: College of Urban Construction and Environmental Engineering, Chongqing University, Chongqing, 400045, China.
authors: Fang
authors: F
authors: Fang
authors: Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA.
authors: Val H
authors: VH
authors: Smith
mesh_terms: D002681:China; D004784:Environmental Monitoring; D005068:Eutrophication; D010839:Phytoplankton / Q000145:classification* / Q000254:growth & development; D045483:Rivers / Q000737:chemistry*; D012621:Seasons
keywords: Phytoplankton assemblages; Reservoir operation; Seasonal succession; Three Gorges Reservoir; Tributary