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
ChlorophyllSeason (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.