the dirt crust

At some point, as I moved up from Death Valley to the high deserts in southern Utah, I began to notice that the dirt had become crusty, like what I’m used to on the snow in Michigan. A subtle thing. Curious. Eventually, I learned that this phenomenon is, to paraphrase Ranger Chris, what all life in the region depends upon.

Ladies and gentlemen, this is the cryptobiotic soil crust, and it occurs in the four states that are part of the Colorado Plateau—a huge hunk of real estate that uplifted, oh, a long, long time ago. Not only is this soil crust critical to life in the region, but it’s also imperiled.

the Colorado Plateau

Here’s how it works: Arid places, like these high deserts, tend to have loose sand blowing around. But in these deserts an incredibly ancient and useful organism—cyanobacteria—is impregnated in the dirt, and when it gets a little moist (rare in the desert) it becomes all happy and sticky. It begins to grow and to wrap its long, slimy fingers (filaments) around those loose sand granules, creating a tangle of filament and granule and binding the whole mess together. Even dried-out filaments still retain their death grip on the sand. sticky filaments

Then fungi and lichen and algae and mold get in on the act, and slowly, over decades, Voilà! crusty, cryptobiotic soil. But the beneficial effects don’t end there. Cyanobacterial crusts hold onto water and add nitrogen to the crust, so they make the soil more fertile (a big deal when “soil” is a bunch of loose dust). I came to appreciate the beauty of such a process during two days of wind that blew dust all over kingdom come. Without the crust, the whole desert would have been a dust storm.

But the worm in the apple (you knew this was coming) is that these soil crusts are fragile. I can attest to that, having tromped on them before I knew better. Once you break the crust, either by foot or by tire, you’re back to loose sand. Dry, easily eroded, and much less fertile.

old footprint (not mine)

Not only that, those beneficial organisms take a long time to reestablish. At least 20 years after one of my misplaced footprints for the cyanobacteria; 45 years for the lichen; and 250 years for moss!

While the national parks are able to do a good job of protecting the soil crusts by prohibiting off-road vehicles, buying out grazing leases, and educating visitors (“Don’t bust the crust” is the tagline), the parks are a small part of the overall picture.

On vast tracts of federal land, no such protection exists. I camped on BLM land and saw the dirt bikers, being the young rebels that they are, who felt no compunction about zipping anywhere they pleased. Signs that prohibited entry were simply broken off. Cattle had no respect for the crust, either, and they meandered all over the place.

The result? According to this website, “…disturbed crusts now cover vast areas in the western United States as a result of ever-increasing recreational and commercial uses of these semi-arid and arid areas. … the tremendous land area currently affected by human activity may lead to significant increases in regional and global wind erosion rates.”

I don’t mind telling you that I feel darned guilty for my part in contributing to the bad karma. I guess leaving only footprints is sometimes still too much.


beautiful cryptobiotic soil





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6 Responses to Dirt

  1. Mary 7 June, 2011 at 3:57 pm #

    Good reads Kate, so enjoy the blogs. Feels at times like I am with you! (for sure in spirit .. you go girl). Had a great visit with Julia a couple of weeks ago in Steve’s/aka South Main Tavern. Told her she was such a sweetheart, I had her on my short list for one of my boys …she said she had a boyfriend … I told her to keep my list open!
    Keep us posted on what you are up to, get to Michigan, you always have a place to stay!

    • Kate 7 June, 2011 at 5:18 pm #

      Actually, Josh was on MY list for Julia, too. Both such great kids.
      Thanks for keeping up with my wandering. So cool to think that Scottville is following along with my journey. I’ll be in W. Michigan, maybe in August. (I’m still trying to put my summer together.)

  2. Cary 4 June, 2011 at 5:09 pm #

    Hi Kate,
    we just returned from two weeks in S. E. Utah and was greatly reminded about the special soil, you end up hopping along on the bedrock when you can. Irony in the more managed BLM areas (even day hiking permits required on Cedar Mesa, with limits) yet there are lots of big ol cow hooves tromping the soil looking for the non existent grass. Would recommend Hovenweep N.M. for a nice low key camping experience with tower ruins. The cliffrose in full bloom and cactus coming. Cary

    • Kate 7 June, 2011 at 5:24 pm #

      Yeah, I did a lot of bedrock hopping, too. Never heard of hiking permits in BLM land. Is that a good thing?

      Hovenweep in definitely on my short list.

      I caught a lot of the cactus bloom, but cliffrose was new to me. I love blossoms with a sweet odor–kind of a sensory two-fer.

      I blasted through Colorado (waved to you guys from the interstate)–you were probably on vaca, and I was cold and wet. Now it’s 96 in Iowa. I have promises to keep in Michigan.

  3. dave and sue sprinkle 3 June, 2011 at 11:23 pm #

    Well written article…we look forward to exploring this area next fall and promise to tread lightly……quite a contrast
    to 30 feet of snow standing in the parking lot of our ski area. We did have a great snow shoe trip to the top last weekend but are looking forward to this weekend with temperatures finally reaching the mid seventies at our cabin.

  4. Anne 3 June, 2011 at 1:06 pm #

    Very interesting article! I read about “the crust” when I was looking up some NPs that I wanted to see next year and I’ve been always wondering what it’s all about. Now I know and I’ll make sure not to leave any foot prints!