Month

Mean Plankton concentration (ppm) 1978-1989 (±SD)

Mean Plankton concentration (ppm) 1990-2001 (±SD)

1

1.33 (0.78)

2.86 (1.68)

2

2.52 (1.71)

4.24 (2.72)

3

3.60 (1.71)

3.18 (1.74)

4

6.22 (1.79)

5.19 (3.32)

5

6.19 (1.91)

4.41 (2.72)

6

1.88 (0.61)

1.98 (0.89)

7

1.23 (0.43)

1.49 (0.51)

8

0.96 (0.41)

1.12 (0.26)

9

0.92 (0.27)

1.36 (0.54)

10

0.90 (0.37)

1.37 0.49)

11

0.88 (0.29)

1.40 (0.49)

12

0.85 (0.28)

1.25 (0.50)