Figure 1

Figure 1. Water transparency in June-September measured as Secchi depth (m) between years 1903 and 2004 in the different regions of the Baltic Sea. Sampling stations are indicated on the map with different colours for each of the regions. Secchi depth observations (m) are plotted against the year of observation and the curves fitted with non-linear smoothing and shown with 95 % confidence intervals. The number of observations (n) is shown on each figure.