Land reclamation has also led to the deterioration of the environment in oceanic areas. "Land reclamation is a process in which natural and man-made materials are added to coastal areas and waterfronts in an attempt to make them more solid, essentially creating new land surfaces," said Cui Shenghui, a researcher with the CAS' Institute of Urban Environment. He warned that over-reclamation of coastal land will influence the biological diversity of marine life and, possibly, change the ocean's functions.
Coastal shallows, mangrove forests and inter-tidal zones are where the land and the sea meet. When artificially separated, nutrients from the land no longer flow into coastal waters, threatening crabs, shrimp, clams and other organisms, which rely on this source of food. "This has an impact on the ocean food chain and the fishing industry, not to mention some land-dwelling animals," Cui noted.
Jiang said that salt and fresh water ecosystems are also intimately connected. "For example, the Chinese sturgeon lays its eggs in the Jinsha River, a tributary of the Yangtze River that is China's largest waterway, and empties into the East China Sea. But land reclamation can affect the migratory patterns of these fish stocks," he said,
Furthermore, land reclamation has seen a deteriorating quality in sea water. According to Xia Zhen from the Guangzhou Maritime Geological Survey Bureau, aquaculture farms built on the new land should be blamed for the rising occurrences of rapid algae accumulation.
According to Jiang, restricting the tides artificially means nutrients accumulated in river deltas flow more quickly into the sea. Particularly if reclaimed land is used for aquaculture, large quantities of organic matter and nutrients will be carried by the tides to the ocean, triggering massive algal blooms, threatening ocean organisms and causing huge drops in fish and shellfish populations.
Besides ecological impacts, the geological problems related to reclamation also loom.
Some residential communities built on reclaimed land in Shenzhen, south China's Guangdong Province, were found to have subsided due to poor foundations. In the Netherlands and Japan, construction will not start until 30 years after reclamation to allow enough time for new land to become firm. But in China, the waiting period has been shortened to 10 years.
Recognizing these problems, the Chinese Government vowed to establish sound systems to monitor oceanic ecosystems last November. It vowed to better protect the natural environment and manage land reclamation, and banned reclamation in regions where the ocean has a low self-purification capacity.
China should limit land reclamation and strengthen environmental assessment systems in ecologically fragile and sensitive coastal regions that have important ocean resources such as mangroves and nationally protected animals, Ma suggested.
Liu Yun, a researcher from the CAS' South China Sea Institute of Oceanology, called for a comprehensive review to be held before the reclamation projects start in order to avoid future grievous results.
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