Abstract: Different nutrient media experimentally were N, P and Fe-limited
conditions and a serial of diluted BG11 media. The cell change of morphology
and life history, cell number, cell color and cell area of Microcystis were
analyzed quantitatively. First, the effects of nitrogen, phosphorus and iron
depletion were distinctively different. Phosphorus and iron depletion caused
more special division cells, slowly growth increasing, the easier change of
bigger cell area. Second, the nitrogen and iron depletion could make the color
of alga from green to brown. Finally, according to the resource competition and
Monod equation, Microcystis kinetics of phosphorus and iron were also examined.
K_s and μ_{max} of phosphorus
absorption were 0.0352 μmol/L, 0.493 d^{-1} respectively;
iron absorption: 0.00323 μmol/L, 0.483 d^{-1}. In a word,
some evidences of the Microcystis bloom privilege in certain nutrient
conditions were indicated in the experiments. The privileges were determined as
the reviving under the adverse circumstances through the special division, the
various nitrogen resources, and the lower kinetics of phosphorus and iron than
that of most of other algae. The conclusions provided the scientific basis for
preventing and managing Microcystis bloom in freshwater.
