Phytoplankton composition of the Itaparica and Xingó reservoirs, São Francisco River, Brazil.

Nkc Aragão-Tavares,An Moura,Js Severiano

doi:10.1590/1519-6984.19413

Abstract

The installation of dams causes changes to the integrity of rivers and to the water cycle, performing an instrumental role in the organization of biological communities, including that of phytoplankton. In the present study, we analyzed the taxonomic composition of phytoplankton in two hydroelectric reservoirs on the São Francisco River, Itaparica and Xingó reservoirs. Samples were collected at quarterly intervals between December 2007 and September 2009, at 12 sampling stations in each reservoir, totaling 92 samples. We identified 110 species in the Itaparica reservoir and 136 in the Xingó reservoir, of which diatoms followed by green algae, played a major contribution to both reservoirs. Most of the species is rare and/or occasional. In the Itaparica reservoir, there were no very frequent species, although in the Xingó this category was represented by the diatoms Aulacoseira granulata (Ehrenberg) Simonsen and Fragilaria crotonensis Kitton. These results show that, despite the similarity in the composition of phytoplankton, the reservoirs studied certainly differed regarding their environmental conditions.

Highlights

IntroductionThe impacts of hydroelectric reservoirs on aquatic environments have been extensively studied (Kelly, 2001; Tundisi and Matsumura-Tundisi, 2003; Li et al, 2012), since the installation of dams causes changes to the integrity of Rivers and to the water cycle, playing an instrumental role in the organization of biological communities (Tundisi et al, 2002; Pringle, 2003; Silva and Cecy, 2004; Magilligan and Nislow, 2005)
Among the communities that best express the behavior of a water body is phytoplankton community, since they respond quickly to changing environmental conditions, both of natural and anthropogenic origin (Chellappa et al, 2009; Popovskaya et al, 2012)
The present study was conducted for two consecutive years, and two reservoirs (Xingó and Itaparica) were monitored in order to characterize the phytoplankton community in these environments, through the analysis of taxonomic composition, an important tool commonly used in monitoring programs to assess water quality worldwide

Summary

Introduction

The impacts of hydroelectric reservoirs on aquatic environments have been extensively studied (Kelly, 2001; Tundisi and Matsumura-Tundisi, 2003; Li et al, 2012), since the installation of dams causes changes to the integrity of Rivers and to the water cycle, playing an instrumental role in the organization of biological communities (Tundisi et al, 2002; Pringle, 2003; Silva and Cecy, 2004; Magilligan and Nislow, 2005). Knowledge about the diversity and distribution of phytoplankton in water bodies is of fundamental importance for a better understanding of the functioning mechanisms of these ecosystems, possibly. Phytoplankton of São Francisco River acquiring a predictive character about the possible changes that may occur in the environment (Huszar et al, 2000). The present study was conducted for two consecutive years, and two reservoirs (Xingó and Itaparica) were monitored in order to characterize the phytoplankton community in these environments, through the analysis of taxonomic composition, an important tool commonly used in monitoring programs to assess water quality worldwide

Study area

Data collection and analysis

Results and Discussion