Table 2 Results of the one-factor ANOVA (diurnal vs. nocturnal) for testing differences in some dominant gastropods and bivalves monthly abundance in diurnal and nocturnal samples collected in a Zostera marina bed from March 2000 to 2001

Jujubinus striatus

25

 Diurnal versus Nocturnal

1

2.42 10⁸

2.42 10⁸

25.58

<0.001

 Error

23

2.18 10⁸

9.47 10⁶

Nassarius pygmaeus

25

 Diurnal versus Nocturnal

1

1.56 10⁸

1.56 10⁸

62.78

<0.001

 Error

23

5.72 10⁷

2.49 10⁶

Mitrella minor

25

 Diurnal versus Nocturnal

1

1.38 10⁷

1.38 10⁷

25.91

<0.001

 Error

23

1.01 10⁷

4.39 10⁵

Calliostoma planatum

25

 Diurnal versus Nocturnal

1

4.16 10⁵

4.16 10⁵

15.35

<0.005

 Error

23

6.24 10⁵

2.71 10⁴

Rissoa membranacea

25

 Diurnal versus Nocturnal

1

925.64

925.64

0.05

>0.05

 Error

23

4.36 10⁵

1.90 10⁴

Bittium reticulatum

25

 Diurnal versus Nocturnal

1

2.74 10⁴

2.74 10⁴

0.62

>0.05

 Error

23

1.02 10⁶

4.43 10⁴

Smaragdia viridis

25

 Diurnal versus Nocturnal

1

1.05 10⁴

1.05 10⁴

3.98

0.058

 Error

23

6.08 10⁴

2645.50

Rissoa monodonta

25

 Diurnal versus Nocturnal

1

0.037

0.037

0.00

>0.05

 Error

23

5.66 10⁴

2463.08

Nassarius reticulatus

25

 Diurnal versus Nocturnal

1

3.99 10⁴

3.99 10⁴

11.17

<0.005

 Error

23

8.22 10⁴

3572.84

Nassarius incrassatus

25

 Diurnal versus Nocturnal

1

1.03 10⁴

1.03 10⁴

4.96

<0.05

 Error

23

4.78 10⁴

2078.41

Anomia ephippium

25

 Diurnal versus Nocturnal

1

1420.85

1420.85

1.92

>0.05

 Error

23

1.70 10⁴

740.72

Musculus subpictus

25

 Diurnal versus Nocturnal

1

64.36

64.36

0.17

>0.05

 Error

23

8633.48

375.37

Musculus costulatus

25

 Diurnal versus Nocturnal

1

10.36

10.36

0.11

>0.05

 Error

23

2215.48

96.32

Mytilaster minimus

25

 Diurnal versus Nocturnal

1

6.98

6.98

0.23

>0.05

 Error

23

703.02

30.57

Parvicardium scriptum

25

 Diurnal versus Nocturnal

1

24.48

24.48

0.57

>0.05

 Error

23

990.56

43.07

Pectinidae

25

 Diurnal versus Nocturnal

1

53.55

53.55

0.34

>0.05

 Error

23

3622.61

157.50