(MOT) A NATURE NO LONGER SMELLING OF NATURE

A sunflower grow near a coal-fired power plant in Niederaussem, Germany.Bernd Lauter via Getty

Across the globe, human activities are changing the way our planet smells. In Egypt, increasing temperatures are shrinking yields of aromatic jasmine flowers; in France, extreme drought has reduced the production of fragrant, night-blooming tuberose, a major ingredient in many perfumes; in Italy, climatic extremes are altering the characteristic floral, citrusy scent of bergamot.

But anthropogenic factors are also reshaping environmental smellscapes, a word coined in the 1980s to describe the totality of scents in a given geographic area, in ways that are far more subtle—and potentially much more harmful.

While humans largely rely on sight and sound in our interactions with each other and with the world around us, many other creatures rely on smells. Ants, for example, require scents for colony cohesion; turkey vultures let scent guide them to far-away carrion; and male moths use scent to find females hundreds of meters away. “Scent is very important because it mediates so many interactions within an ecosystem,” says James Blande, a chemical ecologist at the University of Eastern Finland.

These scent-based interactions are crucial for the maintenance of ecosystem services that directly benefit humans, from the bees and moths that pollinate crops to the flies and dung beetles that recycle the nutrients from dead and decomposing matter. Intact channels of scent communication are likely also important for the preservation of biodiversity. For example, many rare orchid species use scent to attract the co-evolved pollinators they need in order to reproduce, and scent helps guide monarch butterflies to the single type of plant on which they lay their eggs.

But just as we are discovering how important these chemical communication channels are to the fabric of the natural world—and the many benefits we reap from it—we are also learning how drastically they can be disrupted by our activities, including climate change and air pollution.

Now, scientists are working to document human-induced changes in smellscapes across the planet—to understand how these changes affect communication between different organisms, and to try to figure out which systems are capable of adaptation and which may be at risk of failure.

Historically, researchers in the field of sensory pollution have been largely focused on noise and light, says Jeff Riffell, a sensory biologist at the University of Washington. Odor pollution, on the other hand, “is really hard to get a handle on because you need these big chemical analysis devices that [cost] hundreds of thousands of dollars in order to characterize it.” Plus, he says, “we’re just not very olfactory.”

Despite these challenges, a growing number of scientists are documenting how humans are changing the chemical signals of plants and animals. For example, researchers have discovered that air pollution degrades many of the volatile organic compounds that make up lavender’s characteristic scent, and increasing temperatures dramatically decrease the floral perfumes released by strawberry plants and wild white petunias. Agricultural chemicals, like fertilizers and fungicides, add additional VOCs to the air in fields and orchards around the world. now of this article (Mother Jones) - link - more like this (smell) - link - more like this (Finland) - link