The effect of nitrogen concentration and its interaction with light intensity on population dynamics and polysaccharide content of Microcystis aeruginosa

Figures & data

Figure 1. Population dynamics of M. aeruginosa cultured at four nitrogen concentrations (5%, 10%, 25%, and 100% of nitrogen in BG-11) in combination with two light intensities. The formula in the figure follows four-parameter logistic model. Vertical lines represent ±SE.

Table 1. Summary of three-way ANOVA on the interactions between time, light intensity, and N concentration on cell density.

Effect	df	F	p
Time	17	206.708	<0.001
Light intensity	1	48.343	<0.001
N concentration	3	187.107	<0.001
Time × light intensity	17	5.71	<0.001
Time × N concentration	51	11.154	<0.001
Light intensity × N concentration	3	47.469	<0.001
Time × light intensity × N concentration	51	2.792	<0.001

Figure 2. Contents of soluble extracellular polysaccharide, bound polysaccharide, and total polysaccharide content of M. aeruginosa cultured at four nitrogen concentrations (5%, 10%, 25%, and 100% of nitrogen in BG-11) in combination with two light intensities by the end of the experiments. Vertical lines represent ±SE.

Table 2. Summary of two-way ANOVA on the interactions between light intensity and N concentration on different polysaccharide fractions.

Polysaccharide fractions	Effects	df	F	p
Soluble extracellular polysaccharide	Light intensity	1	2.269	0.151
	N concentration	3	25.05	<0.001
	Light intensity × N concentration	3	3.612	0.036
Bound polysaccharide	Light intensity	1	9.494	0.007
	N concentration	3	9.423	<0.001
	Light intensity × N concentration	3	0.222	0.880
Total polysaccharide	Light intensity	1	8.429	0.010
	N concentration	3	8.316	0.001
	Light intensity × N concentration	3	0.313	0.816