title: Environmental rather than spatial factors structure bacterioplankton communities in shallow lakes along a > 6000 km latitudinal gradient in South America.
abstract: Metacommunity studies on lake bacterioplankton indicate the importance of environmental factors in structuring communities. Yet most of these studies cover relatively small spatial scales. We assessed the relative importance of environmental and spatial factors in shaping bacterioplankton communities across a > 6000 km latitudinal range, studying 48 shallow lowland lakes in the tropical, tropicali (isothermal subzone of the tropics) and tundra climate regions of South America using denaturing gradient gel electrophoresis. Bacterioplankton community composition (BCC) differed significantly across regions. Although a large fraction of the variation in BCC remained unexplained, the results supported a consistent significant contribution of local environmental variables and to a lesser extent spatial variables, irrespective of spatial scale. Upon correction for space, mainly biotic environmental factors significantly explained the variation in BCC. The abundance of pelagic cladocerans remained particularly significant, suggesting grazer effects on bacterioplankton communities in the studied lakes. These results confirm that bacterioplankton communities are predominantly structured by environmental factors, even over a large-scale latitudinal gradient (6026 km), and stress the importance of including biotic variables in studies that aim to understand patterns in BCC.
authors.affiliation: Laboratory of Aquatic Ecology, Evolution and Conservation, University of Leuven, Leuven, Belgium.
authors.forename: Caroline
authors.initials: C
authors.lastname: Souffreau
authors.affiliation: Laboratory of Protistology and Aquatic Ecology, Ghent University, Gent, Belgium.
authors.forename: Katleen
authors.initials: K
authors.lastname: Van der Gucht
authors.affiliation: Laboratory of Protistology and Aquatic Ecology, Ghent University, Gent, Belgium.
authors.forename: Ineke
authors.initials: I
authors.lastname: van Gremberghe
authors.affiliation: Department of Aquatic Ecology and Environmental Biology, Institute for Water and Wetland Research, Radboud University Nijmegen, Nijmegen, The Netherlands.|Aquatic Ecology and Water Quality Management Group, Wageningen University, Wageningen, The Netherlands.
authors.forename: Sarian
authors.initials: S
authors.lastname: Kosten
authors.affiliation: Functional Ecology of Aquatic Systems, CURE, Universidad de la República, Rocha, Uruguay.
authors.forename: Gissell
authors.initials: G
authors.lastname: Lacerot
authors.affiliation: Laboratory of Aquatic Ecology, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil.
authors.forename: Lúcia Meirelles
authors.initials: LM
authors.lastname: Lobão
authors.affiliation: Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Vera Lúcia
authors.initials: VL
authors.lastname: de Moraes Huszar
authors.affiliation: Laboratory of Aquatic Ecology, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil.
authors.forename: Fabio
authors.initials: F
authors.lastname: Roland
authors.affiliation: Department of Bioscience and the Arctic Centre, Aarhus University, Silkeborg, Denmark.|Sino-Danish Centre for Education and Research, Beijing, China.
authors.forename: Erik
authors.initials: E
authors.lastname: Jeppesen
authors.affiliation: Laboratory of Protistology and Aquatic Ecology, Ghent University, Gent, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: Vyverman
authors.affiliation: Laboratory of Aquatic Ecology, Evolution and Conservation, University of Leuven, Leuven, Belgium.
authors.forename: Luc
authors.initials: L
authors.lastname: De Meester
mesh_terms: D001419:Bacteria / Q000235:genetics*; D058645:Denaturing Gradient Gel Electrophoresis; D017753:Ecosystem; D060106:Lakes / Q000737:chemistry / Q000382:microbiology*; D059013:Microbial Consortia / Q000235:genetics* / Q000502:physiology; D010933:Plankton / Q000235:genetics*; D013020:South America