Beachgoers to Qingdao expecting clear blue water will likely be disappointed in two days, as an expanse of green algae is sweeping ashore on the beaches of the coastal tourist destination in east China's Shandong Province.

Overgrown enteromorpha — a kind of green algae, also commonly known as sea lettuce — fills a breeding pond in Qingdao city, East China's Shandong province, July 6, 2011. [China Daily]

Reported to be 70 meters wide and 100 meters long, the algae bloom has blanketed the sea near Qingdao No.1 Beach and dyed green an anchored ship's cable.

The the algae in the beach areas of Qingdao is only a minor part of the current 410-square-km green algae in the Yellow Sea, being blown by a southward wind, which is floating toward Qingdao and is estimated to invade the beach in two days, according to the North China Sea Branch (NCSB) of the State Oceanic Administration.

The NCSB has raised the alert level and continued monitoring the algae's movement by satellite, plane and ship.

The algae, though not toxic nor detrimental to water quality, ravages the ecosystem because it consumes large quantities of oxygen, thus suffocating other marine life.

Shandong Province suffered a severe green algae invasion in 2007 and 2010 that decimated its aquaculture and cost millions of yuan.