Coastal lagoons are transitional zones between riverine and marine systems where nutrients and contaminants
often accumulate in these aquatic environments. In the present study, physical and biochemical data were obtained from the five stations between January and December 2022 for the determination of trophic status in the Akyatan Lagoon. The study results indicated the values of physical and eutrophication-related parameters displayed spatial and temporal variability. The trophic status of Akyatan Lagoon was determined by using two multi-metric classification tools as Trophic index (TRIX) and the Trophic status index (TSI). The calculated TRIX values ranged from 4.88 to 7.90 whilst the TSI values varied between 50.0 and 77.4. The strong and positive correlations between the TRIX and TSI values with their high values strongly suggested hypereutrophic conditions in the ecologically and economically important Akyatan Lagoon caused by contaminated Seyhan River
inflows due to terrestrial nutrients and organic matter inputs.