February 17, 2011

Global phosphorous supply may face shortage

A team of researchers have warned that the world's phosphorous inventories may soon be in short supply and overuse in the industrialised world has become a leading cause of the pollution of lakes, rivers and streams.

Writing in the February 14 edition of the journal Environmental Research Letters, Stephen Carpenter of the University of Wisconsin-Madison and Elena Bennett of McGill University report that the human use of phosphorous, primarily in the industrialised world, is causing the widespread eutrophication of fresh surface water. In addition, the minable global inventories of phosphorous are concentrated in just a few countries and are in decline, posing the risk of global shortages within the next 20 years.

"There is a finite amount of phosphorous in the world," says Carpenter, a UW-Madison professor of limnology and one of the world's leading authorities on lakes and streams. "This is a material that's becoming rarer and we need to use it more efficiently."

Phosphorous is an essential element for life. Living organisms, including humans, have small amounts and the element is crucial for driving the energetic processes of cells. In agriculture, phosphorous mined from ancient marine deposits is widely used to boost crop yields. The element also has other industrial uses.

However, excess phosphorous from fertiliser that washes from farm fields and suburban lawns into lakes and streams is the primary cause of the algae blooms that throw freshwater ecosystems out of kilter and degrade water quality. Phosphorous pollution poses a risk to fish and other aquatic life as well as to the animals and humans who depend on clean fresh water. In some instances, excess phosphorous sparks blooms of toxic algae, which pose a direct threat to human and animal life.