The coast of Qingdao, China is usually known for its beaches – but recently the nation's largest algae bloom blanketed the shores with thousands of tons of sea lettuce. A bloom the size of Connecticut has invaded the Yellow Sea surrounding the coastal town, suffocating its waters with layer upon layer of green algae. The sea lettuce may be harmless to humans, but it poses a danger to the marine ecosystem as it spreads and eventually begins to rot, emitting hydrogen sulphide into the water.
China has experienced algae blooms in the past, most notably in a 2008 instance that threatened the sailing events in the Beijing Olympics. Aside from creating a less than desirable place to swim, the green algae beds choke the water for local marine life and cause severe losses in the abalone, clam and sea cucumber farms that thrive on the shores. The bloom of 2008 caused over $100 million in damage to these farmers alone – not to mention the cost of cleaning up the algae across the region.
Once sea lettuce dies it decomposes and rots, emitting a foul rotten egg smell and producing large amounts of toxic hydrogen sulfide gas. Boats, helicopters and thousands of workers are required to clean up algae blooms – at a cost of $30 million or more.
Over 19,800 tons of algae has already been cleaned up from the Qingdao bloom, which is the largest ever recorded in China. Although scientists aren’t totally sure what caused the algae influx, some hypothesize that seaweed farms could contribute to the problem, as they attract fast growing algae which is dumped back into the open water.