Table 1 Output of the linear model testing the effects of strain, temperature, atrazine and their interactions on intrinsic growth rate µ and interaction coefficient α, for C. striatum and T. thermophila. Significant p-values are in bold and accompanied by the effect size of the model factor, expressed as partial eta squared. The main model factors express differences in µ (intercept) while interaction of these factors with N_start express differences in α (slope)

C. striatum

µ (main factor)

α (interaction with \({\mathbf{N}}_{\mathbf{s}\mathbf{t}\mathbf{a}\mathbf{r}\mathbf{t}}\))

model factors (pcgr ~ …)

df

F-value

p-value

\({{\varvec{\upeta}}}_{\mathbf{p}}^{2}\)

F-value

p-value

\({{\varvec{\upeta}}}_{\mathbf{p}}^{2}\)

Starting density (\({{\text{N}}}_{{\text{start}}}\))

1

-

-

-

144.213

< 2e-16

0.30

Atrazine

2

0.970

0.380

2.064

0.129

Temperature

2

6.099

0.003

0.04

0.452

0.637

Strain

2

8.086

0.000

0.05

6.656

0.001

0.04

Atrazine * Temperature

4

2.799

0.026

0.03

1.046

0.384

Atrazine * Strain

4

1.295

0.272

0.916

0.454

Temperature * Strain

4

0.332

0.857

0.242

0.915

Atrazine * Temperature * Strain

8

0.702

0.690

1.838

0.069

Residuals

330

T. thermophila

µ (main factor)

α (interaction with \({\mathbf{N}}_{\mathbf{s}\mathbf{t}\mathbf{a}\mathbf{r}\mathbf{t}}\))

model factors (pcgr ~ …)

df

F-value

p-value

\({{\varvec{\upeta}}}_{\mathbf{p}}^{2}\)

F-value

p-value

\({{\varvec{\upeta}}}_{\mathbf{p}}^{2}\)

Starting density (\({{\text{N}}}_{{\text{start}}}\))

1

-

-

-

652.510

< 2e-16

0.66

Atrazine

2

6.211

0.002

0.04

25.389

0.000

0.13

Temperature

2

42.767

< 2e-16

0.21

8.985

0.000

0.05

Strain

2

24.608

0.000

0.13

67.994

< 2e-16

0.29

Atrazine * Temperature

4

0.257

0.906

0.685

0.603

Atrazine * Strain

4

3.962

0.004

0.05

7.358

0.000

0.08

Temperature * Strain

4

12.714

0.000

0.13

1.035

0.389

Atrazine * Temperature * Strain

8

1.056

0.394

0.783

0.618

Residuals

329