Variation in Water Quality in an Impacted Coastal Lagoon over the Last Decade (Küçükçekmece Lagoon, Turkey)

Abstract

Küçükçekmece Lagoon, located inside the Istanbul metropolitan area, is connected to the Marmara Sea by a small canal. Due to the construction of a dam on the Sazlıdere stream, which is the most important feeding source for the lagoon, there has been a decrease in freshwater inflow, so the amount of salinity in the lagoon has started to increase. While salinity was around 11 ppt in the surface water of the lagoon in the 2010s, the level of salinity concentration exceeds 17 ppt today which also has an impact on the ecosystem. The aim of this study is to evaluate the water quality changes in Kucukcekmece Lagoon in a decade. The water quality revealed a high spatial and temporal variation in the lagoon and the bottom (ca 18 m) waters were rich in H2S, of which the highest concentration was measured as 215 mg/L. Overall, from the large dataset of water quality for more than ten years, there is an obvious effect of anthropogenic activities and the closure of freshwater inlets on the trophic conditions of the lagoon.

Keywords

• pollution
• water quality
• Küçükçekmece Lagoon
• H₂S