World's lakes 'facing huge ecological threats'

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The Independent Online

More than half of the Earth's lakes and reservoirs now face ecological threats, but the world is paying little attention, an international conference on lake management will hear.

More than half of the Earth's lakes and reservoirs now face ecological threats, but the world is paying little attention, an international conference on lake management will hear.

They are being polluted by agricultural fertilisers, industrial effluent and human waste, while growth indemand for water is draining them, according to a panel of experts at the conference in Japan.

Some have already suffered catastrophe, such as the Aral Sea between Uzbekistan and Kazakhstan in central Asia, whose area has more than halved since the rivers supplying it were diverted for agriculture in the 1960s.

But many more big lakes around the world, including Lake Victoria in Africa, Lake Okeechobee in Florida and Lake Baikal in Russia, are in danger of being destroyed, the panel says.

Lakes in Britain suffer from footpath erosion and vehicle congestion due to tourism but elsewhere the very ecosystems of the lakes are at risk. Although lakes in industrial and developing countries are endangered, only rich countries have the resources to save their lakes, the panel believes.

"Lakes are the most vulnerable and difficult to restore of all natural ecological systems, but they have been widely ignored even as they have deteriorated," said Hideaki Oda, secretary general of the 3rd World Water Forum, which will meet in Japan next year. "Until now, policy makers have focused on rivers, tidal basins and oceans, excluding a discussion of lakes and the possible danger to humans this portends."

This week's conference, one of a series of meetings leading up to the forum, is being hosted by the Research Institute at Lake Biwa, Japan's biggest lake. The panel points out that lakes and reservoirs hold nearly 90 per cent of the fresh water on the planet's surface and they will come under more stress as global demand for water increases in step with world population, which is expected to rise by nearly two billion people by 2025.

"Natural lakes, especially large ones, are of great economic, ecological and cultural importance, with at least one billion people depending directly on them for their livelihood and for drinking water," said Masahisa Nakamura, the Lake Biwa Research Institute's director. "Specifically, lakes are a source of commerce, transportation, recreation, tourism, and food and energy production. They also provide important habitat for a diverse array of plant and animal species."

According to the panel, lakes at risk include Lake Victoria, Africa's largest lake, which is suffering from sewage discharge along all its banks as well as agricultural discharges and the disappearance of its fish while Lake Baikal in Siberia, the world's deepest lake, which contains about one-fifth of the world's reserves of fresh surface water, is plagued by pollution from industrial plants along its shoreline.

Most of the world's lakes suffer from eutrophication, a process in which an over- abundance of nutrients leads to a rapid growth of aquatic plants, which choke off other life leading to a build-up of silt.

Contamination of lakes by toxic substances from industry is the second most cited threat. Human waste and water withdrawal are also causing problems: one study estimates there was a six-fold increase in withdrawals from lakes and rivers between 1990 and 1995, a rate that is twice as fast as population growth.

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