Table 3 Two-way ANOVA tests analysing direct and combined effects of low pH and thermal-stress (+2 °C) on three coralline species: Neogoniolithon sp. (rhodolith), Amphiroa tribulus (articulated) and the CCA Lithothamnion sp. Pmax, maximum gross photosynthesis (μmol O2 cm−2 h−1); RL, Post-illumination Respiration (μmol O2 cm−2 h−1); and Gmax, maximum calcification rate (μmol CaCO3 cm−2 h−1).

From: Coralline algal physiology is more adversely affected by elevated temperature than reduced pH

 

Rodoliths

F

P

Articulated

F

P

CCA

MS

F

P

df

MS

df

MS

df

Source of variation

 Pmax

  pH

1

0.564

3.35

0.08

1

0.255

1.75

0.199

1

<0.001

0.001

0.981

  Temp.

1

5.319

31.5

<0.05*

1

6.298

43.44

<0.05*

1

0.603

83.014

<0.05*

  pH*temp.

1

0.254

1.5

0.232

1

0.001

0.009

0.926

25

0.003

0.428

0.519

  Error

24

0.168

  

21

0.145

   

0.007

  

 RL

  pH

1

0.07

1.804

0.192

1

0.012

0.677

0.419

1

0.005

1.522

0.229

  Temp.

1

1.173

30.393

<0.05*

1

1.478

84.274

<0.05*

1

0.112

36.563

<0.05*

  pH*temp.

1

0.005

0.132

0.72

1

0.028

1.619

0.216

1

<0.001

0.023

0.882

  Error

24

0.039

  

21

0.018

  

25

0.003

  

 Gmax

  pH

1

0.308

19.17

<0.05*

1

0.074

29.6

<0.05*

1

0.029

18.235

<0.05*

  Temp.

1

0.59

36.62

<0.05*

1

1.207

483.14

<0.05*

1

0.111

69.577

<0.05*

  pH*temp.

1

0.001

0.056

0.816

1

0.089

35.58

<0.05*

1

<0.001

0.074

0.788

  Error

16

0.016

  

22

0.002

  

23

0.002

  
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