Cryptobiotic Soil: Watch your step!

Last week, I spent most of a post complaining about people not issuing proper warnings, and in doing so, putting their viewers at risk.  In the days since, I've realized that there was an important safety warning that I should have issued prior to writing about the desert canyons of Southern Utah.  Not your safety, as I've written about nothing remotely dangerous to humans, but for the desert's safety.  When hiking or camping in that region of the country, with its harsh sun, whipping wind, and towering stone walls, it's easy to forget how fragile all ecosystems really are, and that every step you take could potentially set the environment back decades, centuries, or millennia.  In the case of those dry, stony wilds, there is a teeny tiny microorganism that is (almost) unnoticeably holding the desert together, and if you're not careful, you could easily wipe out vast colonies while dragging your tired feet through the sand.

A few days back (post-wise), I was in the Coral Pink Sand Dunes State Park.  Sand dunes are the result of wind having free reign to do whatever it wants with loose sand and fine dirt.  The biggest reason that rolling dunes don't dominate this whole region (as there is enough fine dirt to make many miles of dunes) is a fine crust holding much of the soil in place, made up of opportunistic bacteria living semi-symbiotically with moss and lichen.  This crust, called Cryptobiotic Soil (Crypto, for short), acts as a natural scab preventing the desert from hemorrhaging sand into the surrounding environment.  Here's a picture of what it looks like:

When I say "Crypt" you say "O"!  Crytp! O! Crypt! O!

In the above photo, you can see little Crypto neighborhoods surrounded by loose sand rivers, like a desiccated micro-Venice.  Without those little Crypto pockets, this entire photo would just be of loose sand.  Then, after years of wind gusts and rain, it would just be stone.  Now instead of a few square feet of Crypto, imagine acres of it, with juniper trees, cacti, and Mormon Tea plants growing throughout.  Crypto is everywhere in this landscape, and if it weren't, there wouldn't be a landscape to hold together.

So what is it?  Crypto is created by cyanobacteria that, when wet, move upwards in soil leaving a slime trail.  This trail then hardens in the sun, starting the scab, which allows for moss and lichen growth to follow.  The cyanobacteria then lay dormant until the next rain fall, at which point they start moving around again, forming a newer, higher (fractions of a millimeter) level of crust, which more moss and lichen can grow on.  It is a very slow process spanning centuries.  The highest I've seen in some larger Crypto cities could be measured in inches, which equates to hundreds of years of that bacterial scab holding the sand below it in place.

Aside from providing erosion protection, Crypto also performs the important task of fixing nitrogen in the soil.  For all of you non-farmer out there, sand does not make for the best potting soil.  Yet pinyon pines and juniper trees seem to pop up effortlessly out of the sandy, waterless soil.  What's their secret?  I'll never tell...  No, it's Crypto.  The secret is Crypto.  Aside from making crusty scab slime, the bacteria leaves yummy yummy fixed nitrogen for the plants that want to grow in the stabilized soil.

Now that you know how important Crypto is, and how the Utah desert would be a barren wasteland without it, you're probably wondering how you could do your part to protect it.  That's very responsible of you!  The biggest thing you can do is just leave it alone.  If you walk on Crypto, that's it, you've demolished decades (or centuries) of growth, loosened the soil in and around it, and have condemned it to death by wind gust.  To really hammer that home, here's info from a great article by Jayne Belnap of the USGS:

Because of such slow recolonization of soil surfaces by the different crustal components, underlying soils are left vulnerable to both wind and water erosion for at least 20 years after disturbance (Belnap and Gillette, 1997). Because soils take 5,000 to 10,000 years to form in arid areas such as in southern Utah (Webb, 1983), accelerated soil loss may be considered an irreversible loss. Loss of soil also means loss of site fertility through loss of organic matter, fine soil particles, nutrients, and microbial populations in soils (Harper and Marble, 1988; Schimel et al., 1985). Moving sediments further destabilize adjoining areas by burying adjacent crusts, leading to their death, or by providing material for "sandblasting" nearby surfaces, thus increasing wind erosion rates (Belnap, 1995; McKenna-Neumann et al., 1996).

Scary stuff, right?  So what can you do to help, aside from not visiting the Utah desert?  The easiest thing you can do is: Stay on Trail.  Crypto does not grow on established trails due to the amount of foot traffic they see.  Staying on trail may seem lame, but there's nothing lame about protecting the environment.  And if someone calls you lame for caring, let me know and I'll have a word with them.

That said, if you are unable to stay on trail, here are some other places Crypto doesn't grow.

• Washes - Washes form after a rain storm.  Crypto can't survive in a wash, since it will be swept away every successive storm.  Walk in washes.


• Exposed Rock - Crypto requires soil for the cyanobacteria to move around.  Exposed rocks that don't have soil won't have Crypto.  Walk on those rocks.


• Plants - Oof, this is a tough one and I'm sure fists are already being shaken in my general direction.  Avoid this one as much as you can, since you'll still be doing environmental damage.  That said, the desert is full of scrubby brush.  Scrub brush is a lot more resilient than Crypto.  If you have to choose between one or the other, step on the plant.  It'll bounce back, Crypto won't.

Ok.  I feel like that was a pretty good PSA.  If you didn't click on that link above, you should.  It's a quick read, very informative, and makes no buts about the importance of Crypto.  Here, let me give you the link again.  

So the next time you're in the desert, be Crypto aware.  Don't step on it, don't bother it, don't even look at it funny.  Oh, but you can pee on it: When moistened, the cyanobacterial filaments become active, moving through the soils and leaving a trail of the sticky, mucilaginous sheath material behind. (Belnap)