Why is the sea murky or full of seaweed at Istanbul beaches (Florya, Büyükada) — is it dirty?

To avoid seaweed, swim further from shore where it's usually absent — the sea is considered dirty only if trash is floating on the surface. However, at Florya lifeguards whistle and call swimmers back if they try to go too far out.

Sea cloudiness depends on weather: strong wind and waves stir up natural sediment, not trash. Even murky sea water is cleaner than any pool.

Seaweed doesn't always appear — after a storm it washes ashore along with jellyfish, but beaches get cleaned and it disappears. Büyükada usually has more seaweed than Florya beach.

Seaweed isn't really a downside — it contains minerals that are good for skin. On the islands, wave conditions mean seaweed amounts vary year to year.