title: Bacterial community composition over a dry winter in meso- and eutrophic Portuguese water bodies.
abstract: In order to investigate the bacterial diversity in a number of rivers, reservoirs and lakes in northern and central Portugal during the winter of 2004/5 (atypically dry), we applied molecular methodologies, namely denaturing gradient gel electrophoresis with primers targeting fractions of the bacterial 16S rRNA gene. Environmental parameters such as pH, conductivity, inorganic nutrients, total suspended solids and chlorophyll a were determined in order to characterize the trophic status of the studied water bodies. We found water bodies with oligotrophic to hypereutrophic characteristics. Organisms belonging to the Bacteroidetes and Alphaproteobacteria were found at the highest pH environment. Bacteroidetes were also related to high nutrient concentrations. Verrucomicrobia were associated with the most oligotrophic reservoir and low pH values. Actinobacteria were present in all samples from lakes and reservoirs, indicating its preference for lentic water bodies. Cyanobacteria dominance was related to high pH and conductivity levels. In general the conductivity values recorded in winter 2005 were the highest over recent years and chlorophyll a also reached very high levels. The data emphasize an enhanced risk of eutrophication for the studied water bodies, especially in the subsequent months when the temperature rises.
authors: Department of Biology, University of Aveiro, Aveiro, Portugal. dfigueiredo@bio.ua.pt
authors: Daniela R
authors: DR
authors: de Figueiredo
authors: Mário J
authors: MJ
authors: Pereira
authors: Alexandra
authors: A
authors: Moura
authors: Leonel
authors: L
authors: Silva
authors: Sara
authors: S
authors: Bárrios
authors: Fátima
authors: F
authors: Fonseca
authors: Isabel
authors: I
authors: Henriques
authors: António
authors: A
authors: Correia
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D044822:Biodiversity; D003081:Cold Climate; D004591:Electrophoresis, Polyacrylamide Gel; D005618:Fresh Water / Q000032:analysis / Q000382:microbiology*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011174:Portugal; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012621:Seasons; D014871:Water Microbiology
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S