Getting the Dirt

Sarah, Charlie, and Molly here, reporting from Gunnison, CO. It’s our eighth day into GIGL’s dust collection quest in the great American West (add on six days on the road for S & C—they drove down to the Lower 48 from Anchorage to meet me in Spokane, WA), and already we’re gearing up to hit the tenth of our thirty proposed sample collection sites.

First thing’s first: you may be wondering why on earth a team of cold weather-loving folks like us has decided to devote an entire month to driving around the desert in the hot summer sun—and stranger yet, why we’ve got big, metal boxes packed with dirt and sand. Don’t worry, we’re already quite used to folks asking questions—just take a look at our ride:

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The goal of our trip is easy enough to explain: we’ve set out to identify the major dust source areas of the western United States. Oftentimes we think of dust as the stuff that collects on our bookshelves and countertops when we get behind in our household chores, but in more arid parts of the country, say Oklahoma or southern California, you can see tiny bits of dust and sand all over the place—sweeping through fields along the freeway, collecting in piles in grocery store parking lots, or even blowing across your own backyard.

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We all know that dust is small—sometimes so small you need a microscope to see it—so it may be hard at first to believe that dust plays such a big role in regional and global climate change. But just think: increased temperatures result in drier land conditions (think of how muddy your front yard can get in the rainy springtime, and how dry it becomes later on in the summer). With less moisture to hold soil particles together, the ground material becomes less consolidated and easier to blow away in the wind. The wind is a powerful mode of transport, and can carry tiny bits of sand and clay vast distances—even across continents—but no matter where the dust ends up, there remain a variety of important consequences. For starters, when windblown dust settles on land, it can supply nutrients to the local soil and plant life, and the same goes for dust settling in the ocean, or carried by rivers out to the ocean. Dust also darkens snow and ice surfaces, thereby decreasing Earth’s albedo, or it’s ability to reflect solar radiation.

IMG_2759Many studies have pointed towards increased dustiness on snow cover in the western US over the past two centuries, most likely due to land-use changes like agricultural practices and livestock grazing…but where exactly is all of that dust coming from? And why? Are the most prominent dust sources in areas where humans have made major changes to the landscape? At the end of the summer, we’ll haul our treasure chest full of dirt back to our lab at the University of Michigan and begin our geochemical analyses so that we may answer these important questions. In the meantime, we hope you’ll check back with us as we continue “getting the dirt” on arid regions throughout the American northwest, southwest, and Colorado Plateau. We’re excited to talk a bit more about what we’ve collected so far, and show you some of the incredible landscapes we’ve encountered. Until we next run into some WiFi, this is the GIGL dust team from our big, blue UNIMOG, going clear!

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