Inhaltszusammenfassung

When one looks at the global distribution of soil organic carbon (SOC) stocks, a few patterns emerge (Figure 3.1). The SOC density is not uniformly distributed and nitrogen (N) is strongly associated with it. Hot spots of SOC density exist primarily in the northern higher latitudes and again in smaller pockets in the equatorial regions. But even this general pattern has numerous important exceptions. In the northern hemisphere, for example, regional hot spots exist in central China, in the so...When one looks at the global distribution of soil organic carbon (SOC) stocks, a few patterns emerge (Figure 3.1). The SOC density is not uniformly distributed and nitrogen (N) is strongly associated with it. Hot spots of SOC density exist primarily in the northern higher latitudes and again in smaller pockets in the equatorial regions. But even this general pattern has numerous important exceptions. In the northern hemisphere, for example, regional hot spots exist in central China, in the southwestern forests of the US and in the Pacific Northwest of North America. At the same time in the southern hemisphere, the forests of New Zealand and the Patagonian region in Chile have high SOC densities. One could argue alone from this heterogeneous distribution that processes affecting SOC and N need to be treated on a more regional than global scale. In addition to the carbon (C) stocks, the main factors expected to alter soil C processes in the future are also predicted to change regionally. As an example, when one combines the distribution of C stocks with predicted changes in temperature and precipitation, the overlap can be modeled to show regional hot (red) and cold (green) spots of C release from soils (Figure 3.2). The rcp45 scenario indicates that major changes to soil C processes will occur not only in the tundra, but also significant changes may occur throughout the tropics. Changes in the far northern latitudes will likely create regional sources of CO2 to the atmosphere, whereas in the tropical regions, changes will create sink conditions resulting in CO2 uptake. It also points out some interesting regional hot spots, some of which are considered in regional case studies in this chapter (e.g., Russia, Tibet, Sweden, and Brazil). On the other hand, some regions emerge as areas lacking previous regional consideration, which may indicate the need for future research (e.g., southeastern US, the Balkan states, and Central America). Thus, the objective of this chapter is to focus on the advantages of a regional approach to understand future changes in soil C processes.» weiterlesen» einklappen

Autoren

Klassifikation

DDC Sachgruppe:
Geowissenschaften