Correlation between changes of Chlorophyll-a and transparency in the Southern Caspian Sea

Chlorophyll-a is a main pigment for photosynthetic process in marine phytoplankton and by it either amount of biomass can be estimated or can be considered as an index for trophic level of aquatic ecosystem. In year 1996, 81 secchi disc depth were measured and 1601 samples of chlorophyll-a were collected seasonaly from the southern Caspian Sea. The results showed that average chlorophyll-a in seasonals of spring, summer, autumn and winter were 1.072, 0.550, 1.848, 0.966 mg/m3 and depth of transparency were 6.42, 8.86, 5.62 and 5.22m, respectively. The statistical analysis showed a significant correlation (P<0.01) between these two parameters in the southern Caspian Sea. More studies are needed to find out higher precise correlation.