POOLS AND FLUXES OF BIOGENIC CARBON IN THE FORMER SOVIET-UNION

The Former Soviet Union (FSU) was the largest country in the world. It occupied one-sixth of the land surface of the Earth. An understanding of the pools and fluxes of biogenic C in the FSU is essential to the development of international strategies aimed at mitigation of the negative impacts of global climate change. The territory of the FSU is represented by a variety of climate conditions. The major part of the FSU territory is in the boreal and temperate climatic zones. The climate in the FSU changes from arctic and subarctic in the North to subtropical and desert in the South. From west to east, the climate makes a transition from maritime to continental to monsoon. The vegetation of the FSU includes the following principal types: forest, woodland, shrubland, grassland, tundra, desert, peatlands and cultivated land. Arctic deserts and tundra formations are found in the northern part of the FSU; deserts and semi-deserts are found in the southern part. A framework was created to assess pools and fluxes of biogenic C in the FSU. Under the framework spatially distributed data were analyzed with a geographic information system to isolate ecoregions. The soil-vegetation complexes for the ecoregions were linked to FSU data bases of soil and vegetation C pools and fluxes. The C budget for an ecoregion was established by multiplying the area of the ecoregion by the unit area C content(s) or rate(s) associated with the soil-vegetation complex for the ecoregion. The C pools and fluxes for all the ecoregions were summed to arrive at an initial estimate of the pools and fluxes of biogenic C for 95% of the territory of the FSU. Based on the framework, net primary productivity (NPP) for the FSU was estimated at 6.17 +/- 1.65 Gt C yr-1, the vegetation C pool (live plant mass and coarse woody debris) at 118.1 +/- 28.5 Gt C, the litter C pool at 18.9 +/- 4.4 Gt C, and total soil C pool at 404.0 +/- 38.0 Gt C. The phytomass pool of the FSU was 16% of the global biomass pool. The soil and litter pools of the FSU were 20 and 23% of the global soil and detritus pools, respectively. The NPP of the FSU was 10% of the global NPP. The phytomass, soil and litter densities of the FSU were greater than the world average. The productivity of terrestrial ecosystems in the FSU was slightly lower than the world average.