Soil respiration

River transport of organic carbon, estimated earlier as 0.1 Pg C/yr, brings the sum of non-respiratory outputs to 7 Pg C/yr. Total respiration should therefore be around 50 Pg C/yr. This figure is in agreement with estimates of soil respiration rates determined from compilations of ecosystem types and their measured soil respiration rates (Ajtay et ai, 1979). 

Dorr, H. and Miinnich, K. O. (1987). Annual variation in soil respiration in selected areas of the temperate zone, Tellus, Ser. B, 39,114-121. 

Raich, J. W. and Schlesinger, W. H. (1992). The global carbon dioxide flux in soil respiration and its relationship to vegetation and climate, Tellus, Ser. B, 44,81-99. 

Schlesinger, W. H. and Andrews, J. H. (2000). Soil respiration and the global carbon cycle. Biogeochemistry 48, 7-20. 

Crystalline silica, or quartz, is an abundant mineral found in sand, rock, and soil. Respirable silica dust (particles <5pm) is a known occupational hazard of the dusty trades (e.g., pottery or china manufacturing, work involving sandblasting or abrasive grinding, some construction trades). High level exposure to respirable silica can result in the chronic, progressive lung disease silicosis, characterized by inflammation and fibrosis. 

KEYWORDS C02, groundwater, dimate change, sequestration, soil respiration... 

Hanson PJ, Edwards NT, Garten CT, Andrews JA (2000) Separating root and soil microbial contributions to soil respiration a review of methods and observations. Biogeochem 48 115-146... 

Soil respiration (flush of C02) Field chamber Aerobic incubation for >1 week in lab Indicates soil microbial activity relatively simple equipment conducted in a nonstandard laboratory can be determined in field or in laboratory relatively time-consuming dependent upon organic inputs Parkin et al. (1996)... 

Respiratory quotient (qC02) Calculation from soil respiration divided microbial biomass carbon Indicates activity of microbial biomass determined in nonstandard laboratory with specialized equipment when high, considered an indication of stress on microbial biomass Rice et al. (1996)... 

Parkin TB, Doran JW, Franco-Vizcaino E (1996) Field and Laboratory Tests of Soil Respiration. SSSA Special Pub 49 231-246... 

Soil microbes. Effects include reduced microbial biomass and/or species diversity, thus affecting microbial processes such as enzyme synthesis and activity, litter decomposition, associated with carbon and nitrogen mineralization, and soil respiration ... 

Fortner et al. (2005) reported an inhibitory effect on bacterial growth due to the presence of fullerene nanoparticles at concentration > 4 mg/L, while recently the impact of C60 pollution on soil was described (Tong et al., 2007). The authors analyzed the soil respiration, as well as the enzymatic and the microbial activity... 

Subba-Rao, R.V. and Alexander, M. Effect of DDT metabolites on soil respiration and on an aquatic alga. Bull. Environ. Contam. Toxicol, 25(2) 215-220, 1980. 

Sometimes the risk of waste is estimated on the basis of nutrient cycling tests. As a rule such investigation is carried out for surface waste disposal or its land application. The carbon cycle is very sensitive to harmful compounds. Soil respiration is considered a useful indicator of the contaminants effects on soil microbial activity [56-59]. The production of carbon dioxide can be followed as short-term and long-term respiration tests. 

E) Knapweed may have an indirect effect on other plants because it may modify the soil microbial environment to its advantage. However, studies on soil respiration indicated that there is no obvious enhancement or inhibition of soil microorganisms in the root zone of knapweed. 

Bowden, R. D., K. J. Nadelhoffer, R. D. Boone, J. M. Melillo, and J. B. Garrison. 1993. Contributions of aboveground litter, belowground litter, and root respiration to total soil respiration in a temperate mixed hardwood forest. Canadian Journal of Forest Research 23 1402-1407. 

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