Carbon biomass

Distribution of Carbon. Estimation of the amount of biomass carbon on the earth s surface is a problem in global statistical analysis. Although reasonable projections have been made using the best available data, maps, surveys, and a host of assumptions, the vaHdity of the results is impossible to support with hard data because of the nature of the problem. Nevertheless, such analyses must be performed to assess the feasibiHty of biomass energy systems and the gross types of biomass available for energy appHcations. 

Table 1. Estimate of Net Photo synthetic Production of Dry Biomass Carbon and Standing Biomass Carbon for World Biosphere ...

Human activity, particularly in the developing world, continues to make it more difficult to sustain the world s biomass growth areas. It has been estimated that tropical forests are disappearing at a rate of tens of thousands of hm per year. Satellite imaging and field surveys show that Brazil alone has a deforestation rate of approximately 8 x 10 hm /yr (5). At a mean net carbon yield for tropical rain forests of 9.90 t/hm yr (4) (4.42 short ton /acreyr), this rate of deforestation corresponds to a loss of 79.2 x 10 t/yr of net biomass carbon productivity. 

X 10 Btu/short ton), the solar energy trapped in 17.9 x 10 t of biomass, or about 8 x 10 t of biomass carbon, would be equivalent to the world s fossil fuel consumption in 1990 of 286 x 10 J. It is estimated that 77 x 10 t of carbon, or 171 x 10 t of biomass equivalent, most of it wild and not controlled, is fixed on the earth each year. Biomass should therefore be considered as a raw material for conversion to large suppHes of renewable substitute fossil fuels. Under controlled conditions dedicated biomass crops could be grown specifically for energy appHcations. 

Terrestrial biomass is divided into a number of subreservoirs with different turnover times. Forests contain approximately 90% of all carbon in living matter on land but their NPP is only 60% of the total. About half of the primary production in forests yields twigs, leaves, shrubs, and herbs that only make up 10% of the biomass. Carbon in wood has a turnover time of the order of 50 years, whereas turnover times of carbon in leaves, flowers, fruits, and rootlets are less than a few years. When plant material becomes detached from the living, plant carbon is moved from the phytomass reservoir to litter. "Litter" can either refer to a layer of dead plant material on the soil or all plant materials not attached to a living plant. A litter layer can be a... 

U. Schenk, R. Manderschied, J. Hugen, and H.-J. Weigel, Effects of CO, enrichment and intraspecific competition on biomass partitioning, nitrogen content and microbial biomass carbon in soil of perennial ryegrass and white clover, J. Exp. Bot. 46 987 (1995). 

D. A. Wardle, A comparative assessment of factors which influence microbial biomass carbon and nitrogen levels in soil, Biol. Rev. 67 321 (1992). 

Keywords biomass, carbon sequestration, edge effect, fragmentation, native forest... 

He ZL, Wu J, O Donnell AG, Syers JK (1997) Seasonal responses in microbial biomass carbon, phosphorus and sulphur in soils under pasture. Biol Fertil Soils 24 421 128... 

Sparling GP (1992) Ratio of microbial biomass carbon to soil organic carbon as a sensitive indicator of changes in soil organic matter. Aust J Soil Res 30 195- 207... 

Fig. 2. Effect of Pb (a) and Cd (b) on the dynamics of soil microbial biomass carbon (Cniic) (from Akmal et al. 2005a).

Table 2. Effect of Pb and Cd interaction on soil microbial biomass carbon (mg kg-1) (DAA represents days after heavy metal addition different letters within column indicate that treatment means are significantly different at P < 0.01) (Authors unpublished data, 2006)...

Knight BP, McGrath SP, Chaudri AM (1997) Biomass carbon measurements and substrate utilization patterns of microbial populations from soils amended with cadmium, copper, or zinc. Appl Environ Microbiol 63 39 43... 

Fig. 8.6 The relationship between initial SOC and the net C balance (stover + roots - maintenance requirement), and relative amount of carbon supplied by the roots (maintenance requirement -root biomass carbon) tilled and no-tilled system. Calculations were based on tilled and no-tilled systems with maintenance requirements of 16% and 10% of the SOC, a 11,270 kg grain ha-1 (180 bu acre-1), a harvest index of 0.5, a root to shoot ratio of 0.55, and that non-harvested com stover contained 0.4 g carbon(g plant)-1...

Microbial biomass carbon Chloroform fumigation incubation Indicates soil microbial population various methodologies controls nutrient cycling and biological transformation necessary for soil aggregation dependent upon organic inputs Rice et al. (1996)... 

Rice CW, Moorman TB, Beare M (1996) Role of Microbial Biomass Carbon and Nitrogen in Soil Quality. SSSA Special Pub 49 203-216... 

Klinedinst DB, Currie LA, Direct quantitation of PM2.5 fossil and biomass carbon within the Northern Front Range Air Quality Study s domain. Environ Sci Technol 33 4146 154, 1999. 

It follows that biomass will play a role complementary to other resources such as electricity from nuclear and hydraulic sources, as well as relatively inexhaustible supplies of natural gas, non-conventional oil and oil sands. The end use of these forms will be dictated by a combination of historic development and technological inertia such that substitution products electricity, methanol, hydrogen, or tonnage chemicals like ammonia, will provide the major outlets for biomass carbon... 

The BAT system operates based on principles of aerobic cometabolism. In cometabohsm, enzymes that the microbes produce in the process of consuming one particular compound (e.g., phenol) have the collateral effect of transforming another compound that normally resists biodegradation (e.g., chlorinated ethenes, especially lesser chlorinated ethenes such as dichloroethene or vinyl chloride). The BAT system operates under these principles by sorbing the chlorinated compounds from a vapor stream onto powdered activated carbon (PAC) where they are cometabolically transformed into a combination of end products, including new biomass, carbon dioxide, inorganic salts, and various acids. 

Ecosystem Area, 106 km2 Mean net carbon t/(W-yr)C production 109 t/yr Standing biomass carbon t/hm2 1091 ... 

Jenkinson, D. S. (1988). Determination of microbial biomass carbon and nitrogen in soil. In Advances in Nitrogen cycling in Agricultural Ecosystems. Commonwealth Agricultural Bureau International, Wallingford, UK, pp. 368-386. 

Fang J. Chen A. Peng C. Zhao S. and Ci L. (2001). Changes in forest biomass carbon storage in China between 1949 and 1998. Science, 292, 2320-2322. 

Tufekcioglu, A., J.W. Raich, T.M. Isenhart, and R.C. Schultz (2003). Biomass, carbon and nitrogen dynamics of multi-species riparian buffers within an agricultural watershed in Iowa, USA. Agroforest. Syst., 57(3) 187-198. 

---