title: The common bloom-forming cyanobacterium Microcystis is prone to a wide array of microbial antagonists.
abstract: Many degraded waterbodies around the world are subject to strong proliferations of cyanobacteria - notorious for their toxicity, high biomass build-up and negative impacts on aquatic food webs - the presence of which puts serious limits on the human use of affected water bodies. Cyanobacterial blooms are largely regarded as trophic dead ends since they are a relatively poor food source for zooplankton. As a consequence, their population dynamics are generally attributed to changes in abiotic conditions (bottom-up control). Blooms however generally contain a vast and diverse community of micro-organisms of which some have shown devastating effects on cyanobacterial biomass. For Microcystis, one of the most common bloom-forming cyanobacteria worldwide, a high number of micro-organisms (about 120 taxa) including viruses, bacteria, microfungi, different groups of heterotrophic protists, other cyanobacteria and several eukaryotic microalgal groups are currently known to negatively affect its growth by infection and predation or by the production of allelopathic compounds. Although many of these specifically target Microcystis, sharp declines of Microcystis biomass in nature are only rarely assigned to these antagonistic microbiota. The commonly found strain specificity of their interactions may largely preclude strong antagonistic effects on Microcystis population levels but may however induce compositional shifts that can change ecological properties such as bloom toxicity. These highly specific interactions may form the basis of a continuous arms race (co-evolution) between Microcystis and its antagonists which potentially limits the possibilities for (micro)biological bloom control.
authors.affiliation: Protistology and Aquatic Ecology, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 Gent, Belgium. Electronic address: jeroen.vanwichelen@inbo.be.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Van Wichelen
authors.affiliation: Protistology and Aquatic Ecology, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 Gent, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: Vanormelingen
authors.affiliation: Biological and Environmental Sciences, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, Scotland, UK.
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Codd
authors.affiliation: Protistology and Aquatic Ecology, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 Gent, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: Vyverman
mesh_terms: D064089:Allelopathy; D000898:Antibiosis; D005068:Eutrophication; D046931:Microcystis / Q000502:physiology*; D014871:Water Microbiology
keywords: Biological control; Co-evolution; Cyanobacteria; HAB; Microbial antagonists; Microcystis