Carbon dioxide uptake

The effect of temperature fluctuations on net carbon dioxide uptake is ikustrated by the curves in Figure 18. As the temperature increases, net photosynthesis increases for cotton and sorghum to a maximum value and then rapidly declines. Ideally, the biomass species grown in an area should have a maximum rate of net photosynthesis as close as possible to the average temperature during the growing season in that area. 

FIGURE 22.30 Essential features of the coinpartinenCation and biochemistry of die Hatch-Slack padiway of carbon dioxide uptake in C4 plants. Carbon dioxide is fixed into organic linkage by PEP carboxylase of meso-phyll cells, forming OAA. Eidier malate (die reduced form of OAA) or aspartate (the ami-iiated form) serves as die carrier transpordiig CO9 to the bundle slieadi cells. Within die bundle slieadi cells, CO9 is liberated by decar-boxyladon of malate or aspartate die C-3 product is returned to die mesophyll cell. 

Many estimates of total terrestrial net primary production are available, ranging between 45.5 Pg C/yr (Lieth, 1972) and 78 Pg/yr (Bazilevich et al., 1970). Ajtay ef oZ. (1979) have revised the various estimates and methods involved, they also reassess the classifications of ecosystem types and the extent of the ecosystem surface area using new data and arriving at a total NPP of 60 Pg C/yr. Gross primary production is estimated to be twice net primary production, i.e., 120 Pg C/yr. This implies that about 60 Pg C/yr are returned to the atmosphere during the respiratory phase of photosynthesis. It is well known that carbon dioxide uptake by plants follows daily cycles most plants take up CO2... 

Gavis, J. and Ferguson, J. F. (1975). Kinetics of carbon dioxide uptake by phytoplankton at high pH, Limnol. Oceanogr., 20, 211-221. 

Malate dehydrogenase 1.1.1.38 Pyruvate/carbon dioxide Malate Carbon dioxide uptake... 

Bromacil and isocil have been found to be potent and specific inhibitors of photosynthesis at the chloroplast level [361]. The uptake of carbon dioxide is blocked in Chlorella pyrenoidosa and growth inhibition parallels the inhibition of carbon dioxide uptake. In Euglena gracilis and in spinach chloroplasts, the blockage of oxygen production was noted [361]. 

In order that an alternating copolymer is produced, the metal alkoxide must undergo faster insertion of carbon dioxide than reaction with a second equivalent of epoxide. If the metal alkoxide reacts with a second epoxide or undergoes decarboxylation reactions, ether linkage(s) may be formed. Ether linkages are undesirable as they compromise the properties of the polymer and reduce the carbon dioxide uptake. 

Chave K.E. (1981) Summary of background information on magnesium calcites. In Some Aspects of the Role of the Shallow Ocean in Global Carbon Dioxide Uptake (eds. R.M. Garrels and F.T. Mackenzie), pp. A4-A9. U.S.D.O.E. Conf. 8003115, Natl. Tech. Inform. Service, Springfield, VA. 

Farquhar, G.D., Schulze, E.-D., and Ktippers, M. 1980. Responses to humidity by stomata of Nicotiana glauca L. and Corylus avellana L. are consistent with the optimization of carbon dioxide uptake with respect to water loss. Aust. J. Plant Physiol. 7 315-327. 

For MEA and DBA the equilibrium lies to the right so that regeneration (like Benfield) is conducted at 100°C. Unfortunately, amines which would operate at lower temperatures have lower kinetic factors for carbon dioxide uptake. 

Sarmiento, J., and Le Quere, C. (1996). Oceanic carbon dioxide uptake in a model of century-scale global warming. Science 274, 1346—1350. 

Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) evaluations were performed using Perkin Elmer DSC-2C to obtain the T, T, and A/f. A Du Pont Model 2950 TGA was used to evaluate the total amount of carbon dioxide uptake in polymers. A constant heating rate of 20°C/min was used in both the DSC and TGA evaluations. 

Table 6. Glass transition temperature and carbon dioxide uptake for PMMA as determined by thermogravimetric analyses. Treated in carbon dioxide at 3,000 psi and 25°C for 1 hour.

Figure 8 shows semilog plots of the carbon dioxide uptake as a function of evaluation time. Such plots show a linear correlation of carbon dioxide loss Avith the log of the time, consistent with a purely difiiisive mechanism for the loss of carbon dioxide. 

Grace J., Lloyd J., McIntyre J., Miranda A. C., Meir P., Miranda H. S., Nobre C., Moncrieff J., Massheder J., Malhi Y., Wrigjit L, and Gash J. (1995) Carbon dioxide uptake by an undisturbed tropical rain forest in southwest Amazonia, 1992 to 1993. Science 270,11%-im. 

Table 11.3. Estimates of anthropogenic carbon dioxide uptake rate by the oceans...

Another approach is to increase carbon dioxide uptake by forests to reverse the effects of severe deforestation of the last 150 years. It has been estimated that a rapidly growing rainforest can remove 4-7kg/m year of carbon dioxide from the atmosphere, as compared to a typical crop uptake of 0.8-1.6kg/m year. Thus, vigorous reforestation could assist in increasing the photosynthetic removal of carbon dioxide from the atmosphere [59]. Annual crops also perform photosynthetic uptake of carbon dioxide, but consumption and metabolism of the product(s) and prompt decomposition of the plant wastes promptly return the fixed carbon dioxide to the atmosphere [60]. 

Perhaps measures which promise to produce a relatively small favorable perturbation of the approximately 50% oceanic component of carbon dioxide uptake would have a chance of achieving a more substantial reduction in atmospheric carbon dioxide. Preliminary experiments have shown that provision of soluble iron can dramatically improve this process. Addition of iron sulfate at the 2 nM level to iron deficient but otherwise fertile regions of the oceans doubled the phytoplankton growth [61]. Great care should be taken to try to determine any possibly serious side effects before measures of this kind are undertaken on a larger scale. Promotion of an appropriate mix of these measures will help to limit the continued increase in atmospheric carbon dioxide. 

Box 7.1 Simple box model for ocean carbon dioxide uptake... 

The residence time of CO2 in the atmosphere is about two years, which makes the atmospheric air quite well mixed with respect to this gas. However, a more recent analysis shows that the terrestrial ecosystems have much stronger sinks of carbon dioxide uptake. The details of major ecosystem-level CO2 experiments have been shown recently (Koch and Mooney, 1996). 

Grace, J., Malhi, Y., Lloyd, J., McIntyre, L, Miranda, A. C., Meir, P, and Miranda, II. S. (1996). The it.se of eddy-covariance to infer the net carbon-dioxide uptake of Brazilian rain forest. Global Change Biol. 2, 209-218. 

Grace, J., et al. (1995). Carbon-dioxide uptake by an undisturbed tropical rain-forest in Southwest Amazonia, 1992 to 1993. Science 270, 778-780. 

The question of iron limitation was brought into sharp scientific focus with a series of public lectures, reports by the US National Research Council, papers, special publications, and popular articles between 1988 and 1991. What was resolved was the need to perform an open ocean enrichment experiment in order to definitively test the hypothesis that iron limits phytoplankton growth and nutrient and carbon dioxide uptake in HNLC regions. Such an experiment posed severe logistical challenges and had never been conducted. 

The interaction of bipyridyl herbicides (paraquat and diquat) with photosynthesis is different from that of the electron transport inhibitors. These compounds, with highly negative redox potentials (paraquat E 446mV diquat Eq -349mV), interact in the vicinity of ferredoxin causing a diversion of electron flow from the ultimate electron acceptor NADP. This was clearly seen in paraquat-treated plant material as a progressive inhibition of carbon dioxide uptake (25)... 

Figure 5). Although carbon dioxide uptake rapidly ceased, electron flow from water continued for some time until this system was totally inactivated by the general destruction of cellular integrity (25). Paraquat (and/or diquat) is reduced by a one electron transfer to give the paraquat free-radical. 

Figure 5. Carbon dioxide uptake and evolution by paraquat-treated flax cotyledons, incubated on paraquat in either light of 5.25 Wm (O) or darkness...

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