title: Effects of iron on growth and intracellular chemical contents of Microcystis aeruginosa.
abstract: OBJECTIVE
  To investigate the effect of iron on the growth, physiology and photosynthesis of cyanobacteria.
  
  
  METHODS
  A gradient of iron concentrations was employed to investigate the growth, photo-pigments (chlorophyll A and phycocyanin), and cell chemical contents (C, N, P) of Microcystis aeruginosa in response to different iron additions.
  
  
  RESULTS
  The specific growth rate during the exponential growth phase, as well as the cell chlorophyll A and the phycocyanin content, was limited by iron below 12.3 tmol Fe x L(-1). The growth was inhibited when the iron concentration was at 24.6 micromol Fe x L(-1). The cell chlorophyll A and the phycocyanin content were saturated when the iron concentration was above 12.3 micromol Fe x L(-1) and declined slightly at 24.6 micromol Fe x L(-1). At a low iron concentration (about 6.15 micromol Fe x L(-1) and less), the cell nitrogen and carbohydrate content were iron limited, and the variation of the cell phosphorus content was similar to that of the nitrogen and carbohydrate, with a transition point of 12.3 micromol Fe x L(-1).
  
  
  CONCLUSIONS
  The variation of cynobacteria growth is synchronous with that of the photo-pigments or the cell chemical content, and there exist relationships among photosynthesis, growth and internal chemical content, which could be useful for the growth estimation from the cell characteristics.
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. chong.wang@sjtu.edu.cn
authors.forename: Chong
authors.initials: C
authors.lastname: Wang
authors.forename: Hai-Nan
authors.initials: HN
authors.lastname: Kong
authors.forename: Xin-Ze
authors.initials: XZ
authors.lastname: Wang
authors.forename: Hao-Dong
authors.initials: HD
authors.lastname: Wu
authors.forename: Yan
authors.initials: Y
authors.lastname: Lin
authors.forename: Sheng-Bing
authors.initials: SB
authors.lastname: He
mesh_terms: D002241:Carbohydrates / Q000032:analysis; D003470:Culture Media / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D007501:Iron / Q000494:pharmacology*; D046931:Microcystis / Q000737:chemistry / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis
chemical_list: D002241:Carbohydrates; D003470:Culture Media; D010758:Phosphorus; D007501:Iron; D009584:Nitrogen