Table 1 ANOVAs on the effects of pH (ambient and low pH) and nutrient enrichment (control, moderate and high) on the leaf content of chlorophyll a, chlorophyll b, carotenoids, the leaf growth and specific leaf growth. Analyses of the percentage cover of encrusting coralline algae, non-encrusting algae and total epiphytic assemblages on P. oceanica leaves also include the factor plot (3 levels, random and nested within the interaction pH × Nutrients). *P < 0.05; **P < 0.01; ***P < 0.001. SNK tests are included for significant factors or “pH × Nu” interaction.

pH

1

7.746

7.440**

Nutrient (Nu)

2

1.279

1.228

pH × Nu

2

1.848

1.775

Residual

12

1.041

pH

1

0.192

12.096**

Nutrient (Nu)

2

0.032

2.050

pH × Nu

2

0.035

2.221

Residual

12

0.016

pH

1

4.007

11.788**

Nutrient (Nu)

2

0.491

1.443

pH × Nu

2

0.483

1.421

Residual

12

0.34

Leaf growth

SNK tests

pH

1

0.841

1.247

Control nutrient: ambient pH > low pH

Nutrient (Nu)

2

0.479

0.710

Moderate nutrient: ambient pH = low pH

pH × Nu

2

2.801

4.156*

High nutrient: ambient pH = low pH

Residual

12

0.674

Specific leaf growth ^II

SNK tests

pH

1

0.265

51.776***

^dAmbient pH: control = moderate = high

Nutrient (Nu)

1

0.032

6.232**

Low pH: control = moderate < high

pH × Nu

2

0.019

^d3.628*

Residual

12

0.005

Encrusting coralline algae

SNK tests

pH

1

48014

230.602***

^eAmbient pH: control < moderate = high

Nutrient (Nu)

2

1584

7.606**

Low pH: control = moderate = high

pH × Nu

2

1436

^e6.896**

Plot (pH × Nu)

12

208

2.877**

Residual

36

72

Total non-calcified algae ^II

pH

1

35.876

^f5.561*

^fpH: ambient > low

Nutrient (Nu)

2

36.408

^g5.643**

^gNutrient: control < moderate = high

pH × Nu

2

17.907

2.775

Plot (pH × Nu)

12

6.452

3.032**

Residual

36

2.128

pH

1

1.473

^h38.499***

^hpH: ambient > low

Nutrient (Nu)

2

0.450

ⁱ11.774**

ⁱNutrient: control < moderate = high

Ph × Nu

2

0.048

1.257

Plot (pH × Nu)

12

0.038

1.570

Residual

36

0.024