Abstract
Aim : The effects of nitrogen and phosphorus concentration on growth and microcystin production were investigated in three species of bloom-forming Microcystis isolated from two South Korean freshwater systems. Methodology : Three species of cyanobacteria were collected from Yeongchun Dam and Ankei Dam in Kyungpook Province, South Korea. Culture experiments were conducted at 25 ± 1°C under cool white fluorescent light (ca. 50 μmol m-2 s-1) in media with different concentrations of nitrogen (0 to 20 mg l-1 ) and phosphorus (0 to 5 mgl-1). Cell numbers were determined in a hemocytometer for calculation of growth rate. Microcystinwasanalysed using high pressure liquid chromatography. Results : The highest growth rate (μmax and maximal microcystin production occurred at nitrogen concentrations of 10 and 20 mg I-1 in all three species. The response to phosphorus concentration was more complex. The highest growth rate (μmax of M. aeruginosa, M. ichthyoblabe and M. viridis occurred at phosphorus concentrations of 0.5 mg I-1, 0.1 mg I-1, and 3 mg I-1, respectively. M.aeruginosa also had maximal microcystin production at 0.5 mg I-1 P. In contrast, M.ichthyoblabe and M. viridis had high microcystin production at 0 mg I-1 and at 5 mg I-1 P (the highest tested concentration), and low microcystin production at 0.1 mg I-1 P. Thus at 0.1 mg I-1, M.ichthyoblabe had ithe highest growth rate but produced least amount of microcystin. The types of microcystins produced varied according to species and nutrient conditions. Interpretation: Microcystin production and growth in Microcystis species isolated from South Korea varied according to species and nutrient conditions. These species responded similarly to different nitrogen concentrations, but differently to different phosphorus concentrations.
Original language | English |
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Pages (from-to) | 413-418 |
Number of pages | 6 |
Journal | Journal of Environmental Biology |
Volume | 39 |
Issue number | 4 |
DOIs | |
State | Published - Jul 2018 |
Keywords
- Cyanobacterial blooms
- Freshwater ecosystem
- Microcystin
- Microcystis species
- Nitrogen & Phosphorus