Research Article

Mapping the Fundamental Niches of Two Freshwater Microalgae, Chlorella vulgaris (Trebouxiophyceae) and Peridinium cinctum (Dinophyceae), in 5-Dimensional Ion Space

Table 2

ANOVA P-values, regression coefficients and model fit diagnostics for Peridinium cinctum specific growth rate, μ (d−1) and relative cell density (percent of the maximum) for combined, reduced cubic x quadratic Scheffé polynomial models. Only third order or lower terms significant at 𝑃 < 0 . 0 5 for at least one response are presented. Note that the single component p-values (i.e., NO3, PO4, etc.) are covered under “Linear Mixture”. The data were transformed with an inverse square root function before analysis; thus, regression coefficients with lesser values indicate greater effects. C.V. = coefficient of variance, n/s = 𝑃 > 0 . 0 5 .

Specific Growth RateRelative Cell Density
RegressionRegression
SourceCoefficientsP-valuesCoefficientsP-values

Model<0.0001<0.0001
Linear mixture<0.0001<0.0001
 NO3 13.0 9.8
 PO4 13.5 10.3
 K 1.8 2.4
 Na 2.6 2.2
 Cl 12.7 10.1
K * Na 7.1 0.0257 6.5 0.004
K * Cl 9.3 0.0307n/s
NO3 * PO4 * K 99 <0.0001 81.6 <0.0001
NO3 * PO4 * Na 137.6 0.0002 109.2 <0.0002
NO3 * K * Na −103.3 <0.0001 −89.4 <0.0003
NO3 * K * Cl 91.1 0.0047 82.6 0.0003
NO3 * K * [Conc] 13.7 0.0013 10.1 0.0008
NO3 * Na * Cl 137.1 <0.0001 99.8 <0.0001
NO3 * Na * [Conc] 16.3 0.0002 11.1 0.0003
PO4 * K * Na −94.2 <0.0001 −85.4 <0.0001
PO4 * K * Cl 134.7 0.0003 92.7 0.0004
PO4 * K * [Conc] 10.9 0.0018 6.6 0.0064
PO4 * Na * Cl 124.8 <0.0001 77.6 <0.0001
PO4 * Na * [Conc] 12.6 0.0017 5.9 0.0339
K * Na * Cl −129.2 <0.0001 −103.5 <0.0001
Na * Cl * [Conc] 13.5 0.0003 5.2 0.0419
NO3 * K * (NO3-K) 45 0.001 43.9 <0.0001
NO3 * Na * (NO3-Na) 53.5 0.0003 44.8 <0.0001
PO4 * K * (PO4-K) 47.9 <0.0001 38.6 <0.0001
PO4 * Na * (PO4-Na) 54.5 0.0002 42.7 <0.0001
K * Cl * (K-Cl) −49.1 <0.0001 −37.3 <0.0001
Na * Cl * (Na-Cl) −57.5 <0.0001 −29.3 <0.0001
Lack of Fit<0.0001<0.0001

Std. Dev.1.631.15
Mean8.776.95
C.V.%18.6116.57
𝑅 2 0.940.94
𝑅 2 adj0.900.91
𝑅 2 pred0.800.81