Ecological Archives E085-034-A2

R. C. Thompson, T. A. Norton, and S. J. Hawkins. 2004. Physical stress and biological control regulate the producer–consumer balance in intertidal biofilms. Ecology 85:1372–1382.

Appendix B. Tables showing (Table B1) correlations of monthly values for photosynthetic biomass, diatoms, cyanobacteria, and limpet grazing intensity on the midshore at Port St Mary with physical, chemical, and biological regulators and (Table B2) ANOVA for factors affecting temporal and spatial patterns of photosynthetic epilithic microbial biomass.

Table B1. Correlations (Pearsons r) of monthly values for photosynthetic biomass (extracted chlorophyll), diatoms, cyanobacteria, and limpet grazing intensity on the midshore at Port St Mary with monthly values for physical, chemical, and biological regulators.

 

Air temp.

Sea temp.

Insolation(sunshine hours)

Limpet density

Grazing intensity

Planktonic chlorophyll

Dissolved silicate

Dissolved phosphate

Total inorganic nitrate

 

r values

Photosynthetic microbial biomass

-0.61*
(35)

-0.45
(35)

-0.68*
(35)

-0.09
(23)

-0.29
(22)

-0.36
(34)

0.37
(34)

0.42
(34)

0.37
(34)

Diatoms

-0.37
(24)

-0.45
(24)

-0.47
(24)

0.42
(15)

-0.15
(13)

-0.25
(23)

0.34
(23)

0.39
(23)

0.50
(23)

Cyanobacteria

-0.02
(24)

-0.18
(24)

-0.16
(24)

0.46
(15)

0.13
(13)

-0.20
(23)

0.28
(23)

0.19
(23)

0.35
(23)

Grazing intensity

0.73**
(26)

0.67**
(26)

0.45
(26)

-0.19
(19)

 

 

 

 

 

   Notes: (n) is shown for each correlation. Significant relationships, after Bonferroni correction for multiple tests, are indicated in bold. Overall values for P after correcting alpha for the number of tests performed (either 9 or 4) are given (* equivalent to P < 0.05, and * * equivalent to P < 0.01 after adjustment).

 

Table B2. Analysis of variance for factors affecting temporal and spatial patterns of photosynthetic epilithic microalgal biomass, determined using extracted chlorophyll.

Source

df

MS

F

P

 
Chlorophyll

Season (se)

1

453.60

0.00

no test

Shore level (le)

1

0.03

0.00

no test

Canopy cover (ca)

1

62.90

0.00

no test

Site (si)

1

93.17

34.11

0.03

Date(season) da(se)

2

74.93

27.43

0.04

Se × le

1

8.68

0.00

no test

Se × ca

1

5.26

0.00

no test

Se × si

1

7.82

2.86

0.23

Le × ca

1

0.19

0.00

no test

Le × si

1

192.38

3.88

0.19

Le × da(se)

2

15.98

0.32

0.76

Ca × si

1

6.35

0.68

0.50

Ca × da(se)

2

12.19

1.30

0.44

Si × da(se)

2

2.73

0.95

0.39

Se × le × ca

1

1.40

0.00

no test

Se × le × si

1

27.94

0.56

0.53

Se × ca × si

1

15.57

1.66

0.33

Le × ca × si

1

10.86

45.03

0.02

Le × ca × da(se)

2

7.05

29.25

0.03

Le × si × da(se)

2

49.58

17.25

0.00

Se × le × ca × si

1

5.61

23.25

0.04

Le × ca × si × da(se)

2

0.24

0.08

0.92

         

RES

512

2.88

   

TOT

543

     

   Notes: Data were not transformed, Cochrans C = 0.14, P < 0.01. For Student-Newman Keuls comparisons of se × le × ca × si interaction see Fig. 2 in text. Comparison are between season: summer versus winter, shore level: upper versus lower and areas which were covered by Fucus canopy and adjacent areas of open rock, at two moderately exposed rocky sites (Port St Mary and Derbyhaven) on two sampling dates nested within each season (summers and winters of 1993 and 1994). Significant differences are shown in bold. All data are recorded at sites on the Isle of Man.



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