İznik Lake algal bloom indicates water pollution in Turkey

Turkey's fifth‑largest lake, İznik Lake in the Marmara region, has turned turquoise as cyanobacterial algae have surfaced in a massive bloom.

Bursa Uludağ University environmental engineer Doç. Dr. Efsun Dindar explained that the cyanobacteria, which normally remain at the lake bottom, rose to the surface because low oxygen levels there prevent normal photosynthesis. She said, "Alg patlamaları normalde ilkbahar aylarında doğal olan olaylardır. Ancak süresinin uzaması, daha yoğun olması ve özellikle yaz aylarında baş göstermesi, aynı zamanda oradaki gölde kirlilik olduğunun bir göstergesidir."

The bloom is linked to reduced water levels, uncontrolled fertilizer use on surrounding agricultural fields, and increased phosphorus and nitrogen from waste runoff. The dense surface layer threatens aquatic life, raising the risk of fish kills. Local café owner Bekir Uslu noted, "Şu an turkuaz mavisi oluştu gölde… Herkesi bu güzelliği görmeye İznik'e davet ediyorum," highlighting the temporary scenic appeal despite ecological concerns.