Carbon, inventory

The oceanic carbon inventory was presented in Table 15.3. Most of the carbon is inorganic (98%), predominantly in the form of bicarbonate (87%), and is located in the intermediate and deep waters. Of the 2% that is organic, the majority is DOC (see Table 23.2). At present, the ocean is acting as a net sink for atmospheric CO2. In the modern-day carbon cycle, the sole oceanic sink fitr carbon is burial in the sediments in the form of detrital biogenic PIC and POC. 

More recently Cass, Boone and Macias constructed a very detailed carbon inventory for Metropolitan Los Angeles in order to estimate the amount of primary elemental and organic carbon in this urban area ( ). Over 50 source types were included in this emission Inventory. A particulate lead emission inventory was also constructed and used as a tracer for primary automotive exhaust. They compared the ratio of organic carbon to elemental carbon and lead from the emission estimates to that measured in the atmosphere during winter mornings. In that study the sampling time and location were chosen in order to measure... 

The dynamics of the carbon inventory in the reactor, expressed in terms of the catalyst activity ft, are described by the following nonlinear ordinary differential equation... 

Figure 6.3. Soil organic carbon inventory to 1 m depth by parent material category, for California and globally. Well-drained soils in California (white bars) are from the Soil-Vegetation Survey data set, n = 568, well-drained soils only. Worldwide data (gray bars) are from Zinke et al. (1984), n = 2995, which includes the California Soil-Vegetation Survey data, all drainage classes. Reprinted from Torn et al. (1997).

Davidson, E. A., and Ackerman, I. L. (1993). Changes in soil carbon inventories following cultivation of previously untilled soils. Biogeochemistry 20(3), 161-193. 

Photochemical transformation of organic compounds and in particular PAHs on ice, as a medium, has not received much attention from the photochemical community. As a result, information on such transformations is limited. Astrophysical research on water ice, on the other hand, has evolved at a rapid pace in recent years after its discovery on outer solar system bodies and in interstellar space [21-23]. A recent review article by Klan and Holoubek [24] on ice photochemistry provides the current knowledge on the distribution, accumulation, and chemical/photo chemical transformation of persistent bio accumulative and toxic compounds in water ice. Since PAHs constitute a substantial portion of the interstellar carbon inventory [25,26], their photochemical behavior is of paramount importance in the radiative processing of interstellar ices. 

The total uptake of the crust is calculated here as 0.355 g/100 g, which is slightly above the estimate made by Staudigel et al. (1989), and also similar to the total carbon uptake of the oceanic crust inferred by Alt and Teagle (1999) and for the Troodos ophiolite (Bednarz and Schmincke, 1989). The above extrapolation of data for intermediate depths (lower extrusive crust, sheeted dikes) does not contribute major uncertainties to the total flux estimate, because most of the carbon inventory is located in the upper 600 m of the crust, and, therefore, most of the uncertainties lie in this depth interval. 

While radiocarbon is not nearly as valuable to this exercise as it is in the case of the ocean, it does have a role to play. More than half of the terrestrial carbon inventory is stored in soils. The humus in soils consists of a host of complex organic compounds. The evolution of storage in this reservoir will be driven by two competing impacts. Increasing planetary temperature will lead to more rapid oxidation of these humic compounds and hence will tend to drive down the planetary inventory. In contrast, increasing plant growth will lead to increased storage of new humic compounds and hence tend to drive up the inventory. 

Ocean carbon models calculate changes in the oceanic carbon inventory. When these changes, together with changes in the atmospheric carbon inventory (from atmospheric and ice core CO2 data), are subtracted from the emissions of carbon from fossil fuels, the result is an estimate of the net annual terrestrial flux of carbon. 

Attempts have been made to incorporate phase change materials with the activated carbons inside the ANG tanks in order to remove (or supply) the heat from (or to) the carbon so that the carbon remains isothermal during the fill-discharge process [41]. This, however, lowers the carbon inventory in the tank and increases system cost. Instantaneous heat transfer between the carbon and the phase exchange material may also not be practically feasible. 

Mars (2.23 x 10 cm ). Most of Earth s surface carbon inventory is found in the crust, primarily as carbonates, with a total carbon abundance similar to that of CO2 in Venus atmosphere (0.7 x 10 cm" ). Despite this similarity, we do... 

The distribution of trees in a landscape has a significant effect on carbon inventories, with higher inventories generally present under tree canopies (e.g., Liski, 1996). The effect of tree distribution is particularly pronounced in savanna ecosystems (Kellman, 1979 Bird et al, in press Bird and Pousai, 1997). The distribution... 

The above discussion suggests that depending on the sampling and analytical protocols used to estimate carbon inventories at the same single site, the results might easily differ by 10-20%. To this uncertainty must be added the inherently high variability in the SOC pool at all spatial scales in response to the factors outlined in preceding sections. 

Even when an attempt is made to control variables in the manner proposed above, there will still be local variability that cannot be encompassed if sampling is restricted to a few soil pits. Liski (1996) has suggested, for a boreal forest on a sandy substrate in Finland, that a minimum of 30 samples are required for a 10% confidence interval on the mean value obtained for the carbon inventory, and the number of samples required is likely to be higher than this for more heterogeneous tree-grass ecosystems. Carter et al. (1998) found that 15 random soil samples were required from 1° X 1° grid cells in Queensland (Australia) to define the average SOC content of a cell to within 10% of the true mean, while about 40 samples were required for an estimate to within 5% of the mean. 

Figure 8 shows results from over 700 individual samples bulked into six regional samples covering a large climatic gradient in western Canada. These results show a decline in the carbon inventory of the 0- to 5-cin depth interval consistent with the decrease... 

Figure 9 compares results obtained using this approach from sandy soils in different climatic regions. Carbon inventories increase from water-limited savanna sites toward both the humid tropical site and the cold high-latitude site. In addition, the proportion of the total inventory in the 0-.5 cm interval is higher in the cold high-latitude site than in the low-latitude sites. Both these observations are in accord with the trends to be expected from discussion in earlier sections, with the development of thick litter and O-horizons in high-latitude soils and their absence in lower-latitude soils. 

---