Fun with Algae on the Chinese Seaside

Since 2007, the arrival of summer brings with it massive carpets of bright green algae that dominate much of the coastal areas of the Shandong Province, on China’s northeast coast. Like clockwork, as the water exceeds a certain temperature, these thick, stringy masses of algae appear and cover (literally) the province’s beaches, including those in the city of Qingdao.

This “sea lettuce,” as it is referred to in Chinese, is considered harmless to humans, and so most beachgoers seem to take it all in stride. Many are often seen covering themselves from head to toe or having seaweed fights.

Those less pleased with the annual occurrence are the fishermen and Qingdao government officials, as it has ended up being much more than a nuisance. To begin with, vast areas of algae absorb incredible amounts of oxygen within the water, which can cause many shallow-water sea life to asphyxiate. After the massive algae bloom in 2008, research conducted by the Chinese Academy of Fishery Sciences revealed an estimate of US$100 million in damage and losses for clam, abalone, and sea cucumber farms in the region, reports the New York Times.

And once the season has passed and these huge masses of algae begin to decompose, they produce toxic hydrogen sulfide gas, which smells very much like rotten eggs. Countless tons of the stuff then need to be cleaned up and hauled away. To give an idea of what this can require, in the summer of 2008, just before Olympic sailing events hosted by the city of Qingdao, over 10,000 army personnel were put to work clearing the algae as fast as they could so waters were clear for the competitions. This was accomplished with the help of bulldozers, boats, and even helicopters. None of which are free. Olympics or not, the annual cleanup requires thousands of workers and costs millions.

Research has been conducted over the past several years to provide answers as to why the algae appeared so suddenly and became so widespread. The epidemic was first seen in 2007, coinciding with the time that seaweed farmers on the coast well south of Qingdao started going further offshore to clean their rafts. They use these rafts to grow Porphyra, an edible seaweed more commonly known as “nori.” While solid details are lacking, researchers believe that the rafts also attract the green algae, which in turn utilizes nutrients leftover from seaweed farming activity.

The algae also feeds on phosphates and nitrates from pollution in nearby waters—mainly from wastewater and fertilizer runoff. Some believe that increases in seaweed cultivation (and perhaps increases in amounts of pollution) are the major culprit here. And the fact that the algae has begun to bloom offshore has allowed it to drift further north, in some years covering ever-larger swathes of coastline on the Shandong Peninsula. These conditions, when combined with the seasonal rise in water temperatures, seem to be the perfect recipe for this phenomenon.

So it seems these algal blooms are here to stay, unless drastic measures are taken to tackle the problem at the source. In the meantime, you’ve got to admire the fun loving, industrious spirit of the Chinese. Not only do many enjoy covering themselves in the algae, others are fighting back by selling and eating it.

  • Willieaames


  • tomsawyer

    Soaring heat and seaside, Blessing of Almighty 🙂