**4. Conclusions**

In this study, due to rapid industrialization and population growth, a significant deterioration in water quality has been observed since the 1990s. From the large dataset of water quality for more than ten years, exposure to wastewater discharges and the closure of freshwater inlets were shown to be related to adverse effects on the water quality in the lagoon. These changes are having a serious effect on the ecosystem dynamics, revealing a shift in local species.

**Author Contributions:** Conceptualization, R.A. and M.A.; methodology, L.K., E.G.O., and A.O.Ç.; investigation, L.K., E.G.O., and A.O.Ç.; writing—original draft preparation, R.A., M.A., L.K., E.G.O., and A.O.Ç.; writing—review and editing, R.A., M.A., E.G.O., L.K., and A.O.Ç.; visualization, E.G.O.; project administration, E.G.O. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Acknowledgments:** The authors kindly acknowledge Anıl Algedik and Alev Cansu Atar for their kind help in sampling and laboratory work.

**Conflicts of Interest:** The authors declare no conflict of interest.
