A study on water quality and trophic state of Akgöl Lagoon (Mersin, Turkey)

This study aimed to determine the physicochemical characteristics of the water quality and trophic state of Akgöl Lagoon located in the eastern Mediterranean. Cluster analysis clearly revealed the spatial heterogeneity classifying sampling stations as saline and freshwater/brackish water sites. A multivariate analysis of variance followed by principal component analysis supported that salinity was major factor affecting physicochemical water quality variations in the lagoon. As salinity was mainly governed by freshwater inflows depending on agricultural irrigation, it can be proposed that water quality was significantly influenced from freshwater use by human activities. The parameters used as predictors (total nitrogen, total phosphorus, chlorophyll <i>a</i> and Secchi disk transparency) yielded different trophic states for the lagoon. However, as chlorophyll is a better predictor than the other indices, it was concluded that the Akgöl Lagoon is at mesotrophic status.