RESUMO
<p><b>OBJECTIVE</b>To observe the effects of iron and phosphorus on Microcystis physiological reactions.</p><p><b>METHODS</b>The experimental conditions were chosen as the light dark cycles of 16 h 8 h, 12 h 12 h, and 8 h 16 h. The cell change of morphology and life history, cell number, cell color, and cell area of Microcystis were analyzed quantitatively. According to the resource competition and Monod equation, Microcystis kinetics of phosphorus and iron were also examined.</p><p><b>RESULTS</b>The longer light time caused more special cell division, slower growth rate, and easier change of bigger cell area. The color of alga was changed from green to brown. Ks and micromax of phosphorus absorption were 0.0352 mircomol x L(-l) and 0.493 d(-1), respectively. Those of iron absorption were 0.00323 micromol x L(-1) and 0.483 d(-1).</p><p><b>CONCLUSION</b>Microcystis bloom is more dominant than other algae.</p>