Welcome to Colorado Mesa University · 2020. 11. 2. · 1.0 c 0.5 0.0 2000 ZUSGS science for a...

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Transcript of Welcome to Colorado Mesa University · 2020. 11. 2. · 1.0 c 0.5 0.0 2000 ZUSGS science for a...

  • ••

    ••

  • Surface disturbances destroy biocrusts and

    they take a LONG time to grow back

  • The replacement of in-tact biocrusts with bare ground

    or early successional biocrusts influences local and regional hydrology

  • ~1860

    ~1000 BC

    ~3000 BC

    ~1920

    ~1000 BC

    ~1850

    ~1920

    Pacific Railway Act - 1862

    Taylor Grazing Act - 1934

    Neff, J. C., et al. "Increasing eolian dust deposition in the western United States linked to human activity." Nature Geoscience 1.3 (2008): 189

  • Porphyry Basin tarn sediments

    5-7x increase in deposition of K, Mg, and Ca (peaking in early 1900s)

    5-10x increase in N and P, mostly since ~1950, (not peaked)

    Lakes in the San Juan Mountains, Colorado

    Al

    Ca

    K

    PN

    (Neff et al. 2008 Nature)

  • •••

    •••

    Dust

    Clean

    Nat

    ural

    ized

    Run

    off

    (BC

    M/d

    ay)

    Mexico’s annual allotment

    LV

    LA

    * Based on pre-2009 dust loading