Sunday, April 11, 2010

lakes in trouble

Lakes - we take them for granted in this country a little bit. We are blessed with good rainfall but many of our lakes are very sick. I came across this very good article on the state of lakes around the world - it makes very sobering reading.

From Janet Larsen
"More than half of the world's five million lakes are endangered.
Over the last half-century, world water use has tripled, expanding faster than population. Today, irrigation accounts for two-thirds of global water use.
Lakes are not only being drained dry. They also are dying from contamination. Farm wastes, sewage and nitrogen fallout from fossil fuel burning fertilize lakes — cause excess algal and plant growth that in turn, depletes water oxygen levels and kills aquatic animal life.
This process, called eutrophication, plagues more than half the lakes in Europe and Asia, 41% of those in South America — and 28% in North America.
Acid precipitation, largely from fossil fuel burning emissions, is killing thousand of lakes. An estimated 120,000 square kilometers of lakes in Norway are acidified to the point where fish stocks have crashed.
Sweden has some 4,000 acidified lakes. In Canada, some 14,000 lakes are severely acidified. The U.S. Environmental Protection Agency estimates that some 70% of sensitive lakes in New York's Adirondack Mountains are at risk of periodic acidification. It also believes that without further reductions in sulfur dioxide emissions the rate of acidification will increase by half or more.
A survey of remote mountain lakes throughout Europe found that even lakes far from human development were acidified by sulfur and nitrogen deposition. Virtually all were contaminated by heavy metals (such as mercury, lead and cadmium) and fly ash particles.
More than two billion people live in countries with chronic water stress. Many of the world's people, especially in developing countries, depend on fish for protein.

There are some very good specific examples of lakes in real trouble in this article, from the 5 million year old Aral Sea which has lost four fifths of it's volume, to West Africa's Lake Chad which has shrunk to a 5% of its former size. A lot of very good information.

One of the biggest threats to our lakes is pollution - from dairy farms, and fertilisers. Time to say no more and let's really get serious about healing our lakes. There is some really good work being done in this regard already, much of it lead by tangata whenua. Thank you.

1 comment:

Bored said...

Great posts on this blog Mars, have also read the ones on the Mokihinui and the eels. Last time I left a comment it was about the long fin, I despair for its survival. Was great to see the post and the links. Well done.

PS I used to catch them but gave up the moment I saw the research, its a wake up call and chance to take some positive action.