Earth Notes: Tiny Particles, Big Impact

Mar 11, 2015

  For those living in the American Southwest, dust is as much a part of the environment as dryness and sunshine. Tiny particles seem to get into everything, including houses, cars, and noses.

While dust can be annoying, scientists believe it plays a vital role in the region’s ecology. It appears to provide essential minerals and chemical compounds to high-mountain ecosystems, just as seafaring salmon bring ocean nutrients high up into freshwater streams.

But how much dust arrives in the mountains makes a big difference. Ongoing research by Colorado’s National Snow and Ice Data Center, as well as the Center for Snow and Avalanche Studies, suggest that increased levels of dust on area snowpacks are dramatically accelerating rates of snowmelt.

A mountain snowpack that’s been hit by a duststorm becomes darker, absorbs more heat, and melts more quickly. This means moisture runs off faster, and less of it is absorbed by underlying soil.

Credit NASA/JPL-Snow Optics Laboratory

The speed-up can play havoc on the storage and release patterns of Southwest rivers and reservoirs. Instead of trickling from snowpacks over time, water disappears in a hurry, resulting in shortages for plants, animals, and people.

Drought is only one source of increased airborne dust. Levels are rising as more land is eroded by off-road vehicles, livestock, and housing developments. On desert grasslands that are left alone, winds pick up hardly any dust. Keeping dust to a manageable level, it appears, may be essential in assuring that southwestern mountains provide enough water to go around.

Earth Notes is produced by KNAU and the Sustainable Communities Program at Northern Arizona University.