title: A review of the global ecology, genomics, and biogeography of the toxic cyanobacterium, Microcystis spp.
abstract: This review summarizes the present state of knowledge regarding the toxic, bloom-forming cyanobacterium, Microcystis, with a specific focus on its geographic distribution, toxins, genomics, phylogeny, and ecology. A global analysis found documentation suggesting geographic expansion of Microcystis, with recorded blooms in at least 108 countries, 79 of which have also reported the hepatatoxin microcystin. The production of microcystins (originally "Fast-Death Factor") by Microcystis and factors that control synthesis of this toxin are reviewed, as well as the putative ecophysiological roles of this metabolite. Molecular biological analyses have provided significant insight into the ecology and physiology of Microcystis, as well as revealed the highly dynamic, and potentially unstable, nature of its genome. A genetic sequence analysis of 27 Microcystis species, including 15 complete/draft genomes are presented. Using the strictest biological definition of what constitutes a bacterial species, these analyses indicate that all Microcystis species warrant placement into the same species complex since the average nucleotide identity values were above 95%, 16S rRNA nucleotide identity scores exceeded 99%, and DNA-DNA hybridization was consistently greater than 70%. The review further provides evidence from around the globe for the key role that both nitrogen and phosphorus play in controlling Microcystis bloom dynamics, and the effect of elevated temperature on bloom intensification. Finally, highlighted is the ability of Microcystis assemblages to minimize their mortality losses by resisting grazing by zooplankton and bivalves, as well as viral lysis, and discuss factors facilitating assemblage resilience.
authors.affiliation: Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Harke
authors.affiliation: James Madison University, Department of Biology, 951 Carrier Dr., Harrisonburg, VA 22807, United States. Electronic address: steffemm@jmu.edu.
authors.forename: Morgan M
authors.initials: MM
authors.lastname: Steffen
authors.affiliation: Stony Brook University, School of Marine and Atmospheric Sciences, 239 Montauk Hwy, Southampton, NY 11968, United States.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Gobler
authors.affiliation: Oregon State University, Department of Microbiology, Nash Hall 226, Corvallis, OR 97331, United States.
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Otten
authors.affiliation: University of Tennessee, Department of Microbiology, 1414 West Cumberland Ave., Knoxville, TN 37996, United States.
authors.forename: Steven W
authors.initials: SW
authors.lastname: Wilhelm
authors.affiliation: Cawthron Institute, Private Bag 2, Nelson, New Zealand and Environmental Research Institute, University of Waikato, Hamilton, New Zealand.
authors.forename: Susanna A
authors.initials: SA
authors.lastname: Wood
authors.affiliation: University of North Carolina at Chapel Hill, Institute of Marine Sciences, 3431 Arendell Street, Morehead City, NC 28557, United States.
authors.forename: Hans W
authors.initials: HW
authors.lastname: Paerl
mesh_terms: D000818:Animals; D017753:Ecosystem; D016680:Genome, Bacterial / Q000235:genetics*; D023281:Genomics; D046931:Microcystis / Q000235:genetics / Q000502:physiology*; D058974:Phylogeography; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D012336:RNA, Ribosomal, 16S
keywords: Cyanobacterial harmful algal blooms; Microcystin; Microcystis