title: Viral control of bacterial biodiversity--evidence from a nutrient-enriched marine mesocosm experiment.
abstract: We demonstrate here results showing that bottom-up and top-down control mechanisms can operate simultaneously and in concert in marine microbial food webs, controlling prokaryote diversity by a combination of viral lysis and substrate limitation. Models in microbial ecology predict that a shift in the type of bacterial growth rate limitation is expected to have a major effect on species composition within the community of bacterial hosts, with a subsequent shift in the composition of the viral community. Only moderate effects would, however, be expected in the absolute number of coexisting virus-host pairs. We investigated these relationships in nutrient-manipulated systems, under simulated in situ conditions. There was a strong correlation in the clustering of the viral and bacterial community data supporting the existence of an important link between the bacterial and viral communities. As predicted, the total number of viral populations was the same in all treatments, while the composition of the viral community varied. Our results support the theoretical prediction that there is one control mechanism for the number of niches for coexisting virus-host pairs (top-down control), and another mechanism that controls which virus-host pairs occupy these niches (bottom-up control).
authors: University of Bergen, PO Box 7800, Department of Biology, N-5020 Bergen, Norway. ruth.sandaa@bio.uib.no
authors: Ruth-Anne
authors: RA
authors: Sandaa
authors: Laura
authors: L
authors: Gómez-Consarnau
authors: Jarone
authors: J
authors: Pinhassi
authors: Lasse
authors: L
authors: Riemann
authors: Andrea
authors: A
authors: Malits
authors: Markus G
authors: MG
authors: Weinbauer
authors: Josep M
authors: JM
authors: Gasol
authors: T Frede
authors: TF
authors: Thingstad
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism / Q000821:virology*; D001435:Bacteriophages / Q000235:genetics / Q000254:growth & development*; D044822:Biodiversity; D002734:Chlorophyll / Q000096:biosynthesis; D000077194:Chlorophyll A; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004279:DNA, Viral / Q000032:analysis / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D005434:Flow Cytometry; D005502:Food; D005947:Glucose / Q000737:chemistry / Q000378:metabolism; D054884:Host-Pathogen Interactions; D010710:Phosphates / Q000737:chemistry / Q000378:metabolism; D012623:Seawater / Q000737:chemistry / Q000382:microbiology*; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D004279:DNA, Viral; D010710:Phosphates; D002734:Chlorophyll; D005947:Glucose; D000077194:Chlorophyll A