Download
1 / 9
90 likes | 199 Vues
Explore physical mechanisms in patterned-ground creation due to frost-induced soil changes, creating hexagonal crack patterns that accumulate vegetation and organic matter, with a gradient in soil thermal properties. Discover the impact of differential frost-heave and cryoturbation on tundra vegetation growth and barren circles. Learn about the increased water flux and pore-water dynamics affecting soil conditions.
E N D
Frost et al. 2013 – ERL Supp. Figure 1 Supplementary Figure 1. Physical mechanisms in patterned-ground.
Frost et al. 2013 – ERL Supp. Figure 1 circle circle inter-circle inter-circle circle circle circle
Frost et al. 2013 – ERL Supp. Figure 1 Sharp microsite contrasts in soil conditions develop due to differential frost-heave (Taber 1929; Peterson and Krantz 2003) circle circle inter-circle inter-circle circle circle circle organic organic silt loam blocky blocky
Frost et al. 2013 – ERL Supp. Figure 1 Initially, on a barren surface, a more or less hexagonal system of cracks develops due to seasonal freezing.
Frost et al. 2013 – ERL Supp. Figure 1 Cracks collect seeds and retain moisture, so vegetation and organic matter accumulate there. This creates a strong gradient in soil thermal properties.
Frost et al. 2013 – ERL Supp. Figure 1 In early winter, downward freezing occurs faster in exposed mineral soils that lack surface organics.
Frost et al. 2013 – ERL Supp. Figure 1 Pore-water is drawn to the advancing freezing-front in circles due to cryostatic suction. Increased water flux to circle
Frost et al. 2013 – ERL Supp. Figure 1 Increased water-flux leads to stronger frost-heave at circles, as the water expands into ice. Differential frost-heave
Frost et al. 2013 – ERL Supp. Figure 1 Cryoturbation is strongest at the circle center. Tundra vegetation grows too slowly to withstand annual disturbance, so circles remain barren.
