Beachgoers in Ocean Beach and across San Diego’s coastal communities have seen large deposits of murky, green algae covering big patches of ocean water in recent weeks. “Green algae is not hazardous,” said lifeguard Lt. Andy Lerum. “It’s a natural occurrence that happens from time to time when the ocean generates its own bacteria. Algae forms on the surface of the water and gets pushed by the wind, then accumulates along the shore.” Lerum said the wind directions determine where the algae deposits occur.