A marine algal bloom commonly known as "red tide" has returned
to Shenzhen bay, causing serious pollution and killing off many
marine plants.
A red tide is caused by a buildup of marine plankton that
consume oxygen while releasing toxic substances into the water,
killing off fish and plant life.
"This is the biggest red tide that has ever appeared off the
city's coast," said Zhou Kai, a marine expert with Shenzhen's
municipal sea fishery environment monitoring station.
He said this marked the third time this year a red tide had
appeared off Shenzhen. The first appeared near Shenzhen bay in
January and another appeared near Dameisha last month.
Based on the monitoring station's observations, the most recent
red tide is mainly west of Shenzhen. The infected area is about 50
sq km. Sea to the east of Shenzhen appears to be free of the
plankton at this stage.
"We strongly urge the public to stay away from the polluted sea
areas and not eat sea products from there," Zhou said.
A red tide has also been spotted near neighboring Hong Kong in
the past few days, with as many as six beaches in Tunmen and
Qingshan Bay being affected.
The government of the Hong Kong Special Administrative Region
has reminded people not to swim in polluted areas.
Zhou said the red tide would recede if it rained. "But the
weather remains sunny and hot, which means the red tide is here to
stay for now," he added.
He said the recent weather conditions were favorable to the
plankton.
A lot of rain has fallen off Shenzhen's coast in recent months,
pulling nitrogen and phosphorous up from the sea bottom. Plankton
feed off these nutrients.
This, compounded with the hot weather, has helped the plankton
breed and spread, Zhou said. He said the red tide would not cause
major economic losses because very few people were breeding sea
fish in the affected areas.
"But the foul smell of the dying algae will be unpleasant for
the people living in the affected areas, and the tide's annoying
red color will also mar the pleasant view," Zhou said.
(China Daily June 7, 2007)
