Table 1 Physicochemical and biological characteristics of the sampling sites (2 m depth)

26/03/2007

10/07/2007

02/04/2007

17/07/2007

°C

6.2

19.6

7.5

20.4

mg l^-1

10.5

9.7

11.7

10

mg l^-1

1.7

2.2

2.1

2.5

mg l^-1

0.2

0.1

0.5

0.2

μg l^-1

2.0

1.0

6.0

4.0

μg l^-1

2.0

3.0

4.0

2.0

μg l^-1

7.0

6.0

21.0

6.0

μg l^-1

0.7

2.7

1.2

0.7

10⁴ cell ml^-1

9.0 ± 0.5

15.0 ± 1.1

2.0 ± 0.1

12.0 ± 0.8

10⁵ cell ml^-1

24.4 ± 0.3

12.3 ± 0.4

35.0 ± 1.2

25.2 ± 2.0

10⁷ part ml^-1

3.7 ± 0.1

5.1 ± 0.4

8.3 ± 0.3

15.3 ± 0.7

10² cell ml^-1

7.5 ± 1.3

6.9 ± 0.6

2.6 ± 1.3

3.9 ± 1.5

10² cell ml^-1

4.9 ± 1.3

18.0 ± 3.1

1.4 ± 0.2

2.9 ± 0.5