The purpose of this project is to: 1.) determine how biological soil crust (BSC) cover changes along an elevation gradient and across seasons, 2.) determine how carbon and nitrogen exchanges of BSC communities vary with temperature along an elevation gradient in arid and semi-arid environments and, 3.) use photosynthetic and respiration rates of BSC communities to determine how the contribution of the BSC communities to whole ecosystem carbon exchange varies across the same gradient and over seasons.
At each sampling site and sampling period a small amount of surface crust (approx. one teaspoonful per sample) was taken from each of 10 locations at approximately 1 meter intervals over a transect. Samples were transported back to the laboratory in plastic bags.
On rare occasions we removed a larger sample, 0.5 liter volume or less, at one or two sampling stations.
Study sites included: Flux tower sites, desert grassland, desert shrubland, juniper savanna, piñon-juniper woodland, ponderosa pine forest, and mixed conifer forest.
The primary objective of this study is to examine the control that substrate quality and climate have on patterns of long-term decomposition and nitrogen accumulation in above- and below-ground fine litter. Of particular interest will be to examine the degree these two factors control the formation of stable organic matter and nitrogen after extensive decay.
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