CO2 source

Pipelines (qv) connect these large EOR projects to natural CO2 sources in Colorado and New Mexico. Industrial point sources of CO2 have also been used for projects in other areas. 

Figure 5 Comparison of HNBR with fluoroelastomer (FPM), NBR and XNBR in Sour Crude Oil (sour gas = 20% H2S + 65% CH4 + 15% CO2). Source Bayer AG, Germany.

Contaminating CO2. The ubiquitous presence of CO2 causes a great difficulty to the experiment. Normal atmosphere contains 0.03% CO2, and a 5-6 ml portion of pure water equilibrated with atmosphere contains 0.06 pmol of CO2. However, the amount of CO2 in buffers and luciferase solutions is much greater. For example, 5 ml of freshly prepared Tris-HCl buffer, pH 7.8, contained 0.13 pmol of CO2 after 20 min degassing, and the value increased to 0.23 pmol when the same buffer was tested one week later (Shimomura et al., 1977). It is strongly advised to eliminate all nonessential CO2 sources from the experimental environment. 

Enting, I. G. (1992). The incompatibility of ice-core CO2 data with reconstructions of biotic CO2 sources, II. The influence of C02-fertilised growth. Tellus 44B, 23-32. 

Taylor, J. A. (1989). A stochastic Lagrangian atmospheric transport model to determine global CO2 sources and sinks - a preliminary discussion, Tellus, Ser. B, 41,272-285. 

Application of SFE necessitates a CO2 source, a pump to pressurize the fluid, an oven containing the extraction vessel, a restrictor to maintain a high pressure in the extraction line, an analyte collection vessel, and an overall system controller. CO2 is drawn from the bottom of the tank with a dip tube because the liquid is the more dense of the two phases. The substantial vapor pressure of the CO2 at ambient temperature helps to displace the liquid into the pump. CO2 remains a liquid throughout the pumping or compression zones and passes through small-diameter metal tubing as it approaches the extraction vessel. A preheating zone in front of the extraction vessel allows supercritical temperature, pressure, and density conditions to be applied immediately to the analyte matrix in the vessel. 

In a parallel set of discoveries, a reflectance band in the visible, similar to that for solid 02, was seen at low latitudes on Ganymede. In addition, a UV feature associated with O3 was seen on Ganymede and on the icy satellites of Saturn. Coupled with these observations was the much earlier discovery of a band indicative of SO2 in ice at Europa and Callisto and the recent discovery of CO2 trapped in the icy surfaces. The SO2 was initially assumed to be due to sulfur ions originating at lo implanted into the ice at Europa, " but the SO2 is also a radiation decomposition product like the O2, as discussed below. " The CO2 source is probably internal as carbon ions have not yet been seen in the plasma. 

Bousquet P., Peylin P., Ciais P., Ramonet M., and Monfray P. (1999) Inverse modelling of annual atmospheric CO2 sources and sinks 2. Sensitivity study. J. Geophys. Res. Atmos. 104(D21), 26179-26193. 

Figure 17 Measured (points) and modeled (curves) soil carbonate values for three soils along an elevation (climate) gradient in the Mojave desert/Great Basin of California and Nevada. Modeled carbonate values based on Equation (14) plus the fractionation between CO2 and carbonate ( 10%o). The elevations (and modeled soil respiration rates that drive the curve Ht) are (a) 330 m (0.18 mmol C02m h ) (b) 1,550 m (0.4 mmol CO2 h ) and (c) 1,900 m (1.3 mmol CO2 m h ). The value of soil organic matter (CO2 source) was about — 21%o at all sites. Note that depth of atmospheric CO2 isotopic signal decreases with increasing elevation and biological CO2 production (Quade et al, 1989a) (reproduced by permission of Geological Society of America from...

When flux measurements are corrected for calm conditions, the net carbon balance may be nearly neutral. One of the studies in an old-growth forest in the Tapajos National Forest, Para, Brazil, showed a small net CO2 source (Saleska et al., in press). The results in that forest were supported by measurements of biomass (forest inventory) (Rice et al., in press). Living trees were accumulating carbon, but the decay of downed wood released more, for a small net source. Both fluxes suggest that the stand was recovering from a disturbance several years earlier. 

House J. L, Prentice I. C., Ramankutty N., Houghton R. A., and Heimann M. (2003) Reconcihng apparent inconsistencies in estimates of terrestrial CO2 sources and sinks. Tellus (55B), 345-363. 

Table 2.2, half of the carhon source for HCO3 comes from CO2 and half from CaCOs. Comhination of these two mass balance concepts requires that about half of the atmospheric CO2 source be involved in CaCOs dissolution reactions and the other half be consumed by dissolution of aluminosilicates or, about half of the HCO3 in river water that has an atmospheric origin has reacted with aluminosilicates (Fig. 2.2). 

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