Red Sea of Galilee Mystery: What's Really in the Water?

Unusual red patches recently spotted on the surface of the Sea of Galilee have raised concerns among beachgoers, but Israel’s Water Authority reassured the public on Monday that the phenomenon is natural and poses no health risk.

According to officials, the discoloration is caused by the bloom of a green microalga known as Botryococcus braunii. This species, known to appear during previous swimming seasons, produces a red pigment when exposed to intense sunlight.

“The red coloration is due to the accumulation of a natural pigment secreted by the algae in response to strong sun exposure,” the authority explained. “This pigment is not toxic.”

Laboratory tests conducted by the Kinneret Research Laboratory found no evidence of any health risk. “No allergic reactions have been reported in areas where the algae has previously appeared,” they added.

The Water Authority emphasized that it is continuing regular monitoring of the lake’s water quality and ecological balance to safeguard all uses of the Sea of Galilee, Israel’s national freshwater reservoir.