Carbon in Desert Soils at Multiple Time Scales

TitleCarbon in Desert Soils at Multiple Time Scales
Publication TypeConference Paper
Year of Publication2005
AuthorsH. Monger C, Kraimer R.A., Serna-Perez A., Herrick JE
Conference NameEcological Society of America 90th Annual Meeting
Date PublishedAugust 7-12, 200
Conference LocationMontreal, Quebec, CANADA
ARIS Log Number185558
Keywordscalcium, carbon, carbonate, inorganic, organic
AbstractIn contrast to soils of humid regions, which contain carbon as organic matter only, soils of arid regions contain carbon as organic matter as well as calcium carbonate (i.e., inorganic carbon). Both organic and inorganic carbon in desert soils occur in pools through which carbon is driven by interacting physical, chemical, and biological processes. Organic carbon is derived from the decomposition of photosynthetic tissue and is removed from soil via microbial decomposition. Inorganic carbon is derived from the precipitation of bicarbonate with calcium (as well as from dust deposition) and is removed from the soil via dissolution and leaching. The amount of organic carbon in desert soils increases with time until it reaches equilibrium with its bioclimatic environment. The amount of inorganic carbon in desert soils also increases with time, but in contrast to organic carbon, it continues to accumulate with time until the soil is destroyed by erosion or until a climatic change occurs. Patterns of carbon moving through these two pools come into focus at multiple scales. At the diurnal scale, soil CO2 emissions have amplitudes up to 80 mg CO2/square meter/hour; at the yearly scale, amplitudes can be up to 200 mg CO2/square meter/hour. At the century scale, soil organic carbon follows major vegetation changes, such as the replacement of grasslands by shrublands. At the millennial scale, bother organic and inorganic carbon pools are controlled by glacial-interglacial cycles. At all scales, carbon in desert soils mirrors the temporal dynamics of ecological processes.