06.18.08
Flowers’ Fragrance Diminished by Air Pollution
In today’s show, adapted from an article written by Fariss Samarrai, Senior News Officer for the UVa News Department, we look at a University of Virginia study, which indicates that air pollution from power plants and automobiles is destroying the fragrance of flowers and thereby possibly inhibiting the ability of pollinating insects to locate flowers, and may partially explain why certain populations of these pollinators are on the decline.
Of the five senses, smell is one that is sometimes taken for granted in our everyday lives. For most animals, the ability to distinguish scents is a large part of their everyday survival function, as has been attested to in an earlier broadcast entitled, “Inside the brain of crayfish.” For insects, the same is true.
A study by Jose D. Fuentes, a professor of environmental sciences at the University of Virginia, and his team of U.Va. researchers, including Quinn McFrederick and James Kathilankal, indicates that air pollution from power plants and automobiles is diminishing the scents of flowers and reducing the distance that flower scents can travel with the wind. They believe that this may be a factor in the declining populations of some wild pollinators, particularly bees – which need nectar for food –in several areas of the world, including California and the Netherlands.
Their study is funded by the National Science Foundation, and appears online in the journal Atmospheric Environment.
Fuentes said, “The scent molecules produced by flowers in a less polluted environment, such as in the 1800s, could travel for roughly 1,000 to 1,200 meters; but in today’s polluted environment downwind of major cites, they may travel only 200 to 300 meters. This makes it increasingly difficult for pollinators to locate the flowers.”
The result, potentially, is a vicious cycle where pollinators struggle to find enough food to sustain their populations, and populations of flowering plants, in turn, do not get pollinated sufficiently to proliferate and diversify.
Other studies, as well as the actual experience of farmers, have shown that populations of bees, particularly bumblebees, and butterflies have declined greatly in recent years. To investigate this, the U.Va. scientists created a mathematical model of how the scents of flowers travel with the wind. The scent molecules produced by flowers are very volatile and they quickly bond with pollutants such as ozone, hydroxyl and nitrate radicals, which destroy the aromas they produce.
This means that instead of traveling intact for long distances with the wind, the scents are chemically altered and the flowers, in a sense, no longer smell like flowers. This forces pollinators to search farther and longer and possibly to rely more on sight and less on smell.
The scientists calculated scent levels and distances that scents can travel under different conditions, from relatively unpolluted pre-industrial revolution levels, to the conditions now existing in rural areas downwind from large cities.
Fuentes said, “It quickly became apparent that air pollution destroys the aroma of flowers, by as much as 90 percent from periods before automobiles and heavy industry. And the more air pollution there is in a region, the greater the destruction of the flower scents.”
So as the industrial age continues, and emerging economies such as China and its reliance on coal fired power plants proliferate; the ecological balance, so precious to the sustainability of the earth will be under attack.
The question remains, will the industrialized nations of the world recognized the impact we have on the world and develop technologies to protect the environment? Or, will we ebb even closer to an ecological doomsday?
You’ve been listening to the Oscar Show, I’m Jacob Canon. Join us next week when our topic will well look at Philander D. Chase, who recently retired as senior editor of the Papers of George Washington, housed at the University of Virginia’s Alderman Library.
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