Math Model Shows Pollution Diminishes Pollination

May 13, 2008

When flowers grow in polluted air the range of their fragrances are diminished. The result is a reduced ability by pollinating insects to follow scent trails to their source. You could say that the scents are gone with the wind.

A recent University of Virginia study, which appeared in the journal Atmospheric Environment, found that air pollution from power plants and autos is destroying the fragrances of flowers. This could explain why wild populations of critical pollinators, especially bees, are declining in parts of the world.

Investigators have created a mathematical model of how scents of flowers travel in the wind. The scent molecules produced by flowers are volatile and they quickly bond with aroma-destroying pollutants such as ozone, hydroxyl, and nitrate radicals.

Scent molecules produced by flowers in less polluted environments can travel up to 2,000 meters, but in environments downwind of big cites, molecules may have a range of only 300 meters. According to UVA’s José Fuentes, "This makes it increasingly difficult for pollinators to locate the flowers," meaning when the scents are chemically altered, pollinators have to search farther and longer.

The result is a vicious cycle: pollinators struggle to find food to sustain their populations, and populations of flowering plants do not get sufficiently pollinated. "It quickly became apparent that air pollution has destroyed the aroma of flowers by as much as 90 percent," Fuentes said. "And the more air pollution there is in a region, the greater the destruction of the flower scents."

Source: Jerusalem Post (May 3)