MCLC: algae bloom

[Denton, Kirk]

MCLC LIST
From: kirk (denton.2 at osu.edu)
Subject: algae bloom
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Source: NYT (7/5/13):
http://www.nytimes.com/2013/07/06/world/asia/huge-algae-bloom-afflicts-qing
dao-china.html

Huge Algae Bloom Afflicts Coastal Chinese City
By ANDREW JACOBS 

BEIJING — In what has become an annual summer scourge, the coastal Chinese
city of Qingdao has been hit by a near-record algae bloom that has left
its popular beaches fouled with a green, stringy muck.

The State Oceanic Administration said an area larger than the state of
Connecticut had been affected by the mat of “sea lettuce,” as it is known
in Chinese, which is generally harmless to humans but chokes off marine
life and invariably chases away tourists as it begins to rot.

Some beachgoers appeared to be amused by the outbreak, at least according
to the Chinese media, which in recent days has featured startling images
of swimmers lounging on bright green beds of algae, tossing it around with
glee or piling it atop of one another as if it were sand.

Local officials, however, are less enthused. Last month, they declared a
“large-scale algae disaster,” dispatching hundreds of boats and bulldozers
to clean up the waters off Qingdao, a former German concession in Shandong
Province that is famous for its beer and beaches. As of Monday, workers
and volunteers had cleared about 19,800 tons of the algae, according to
the Qingdao government. While valued for its nutrition — or as an
ingredient in fertilizers and biomass energy production — algae in large
quantities can prove dangerous as it decomposes, producing toxic hydrogen
sulfide gas. It also smells like rotten eggs.

The green tide, spread over 7,500 square miles is thought to be twice the
size of an outbreak in 2008 that threatened sailing events during the
Beijing Olympics, which took place around Qingdao. At the time, officials
deployed boats, helicopters and 10,000 workers to keep the waters clear
for the competition.

The cleanup costs were later estimated at more than $30 million. Abalone,
clam and sea cucumber farms suffered more than $100 million in damage,
according to a 2011 study by researchers from the Chinese Academy of
Fishery Sciences.

An outbreak in 2009 was even bigger, affecting a stretch of the Yellow Sea
nearly as large as West Virginia.

Although biologists are at a loss to explain the most recent algae bloom,
scientists suspect it is connected to pollution and increased seaweed
farming in the province just south of Shandong. While similar green tides
have been reported around the world, the annual bloom in the Yellow Sea is
considered the largest, growing to an estimated million tons of biomass
each year.

The green tides were first reported in Qingdao in 2007. A key factor is
the high supply of nutrients from agricultural runoff and wastewater. But
those pollutants have been in the Yellow Sea for decades, leading
scientists to look for new triggers.

A group of researchers believe that the algae that washes up around
Qingdao originates farther south in seaweed farms along the coast of
Jiangsu Province. The farms grow porphyra, known as nori in Japanese
cuisine, on large rafts in coastal waters. The rafts attract a kind of
algae called ulva prolifera, and when the farmers clean them off each
spring they spread the fast-growing algae out into the Yellow Sea, where
it finds nutrients and warm temperatures ideal for blooming.

“It feeds off those nutrients and grows bigger and bigger and eventually
you can see it from satellites,” said John Keesing, a scientist at the
CSIRO Division of Marine and Atmospheric Research in Australia who is
studying the green tide with Chinese researchers. “The currents gently
move the algae in a northeastern direction out into the center of the
Yellow Sea. You get a huge amount, and eventually it starts to wash on
shore.”

While farmers have long grown seaweed along the Jiangsu coast for
consumption, the rafts expanded much farther offshore starting in 2006,
which may have contributed to the recent blooms, according to an article
published last May by Mr. Keesing and his colleagues. The answer to
curtailing the blooms may lie in disposing of the algae that clogs the
nori rafts on land.

“We haven’t suggested people stop growing porphyra, but proper husbandry
methods to prevent much of the waste algae from going into sea, that’s
probably the only preventive measure that could be deployed,” he said.