CO2 exchange

The value of E is insensitive to small changes in ocean temperature but is quite sensitive to wind speed over the sea surface (boundary layer thickness, wave action, and bubble formation are functions of wind speed). Therefore changes in surface wind speed accompanying a climate change could affect rates of air-sea CO2 exchange. 

Bonan, G. B. (1995a). Land-atmosphere CO2 exchange simulated by a land surface process model coupled to an atmospheric general circulation model, j. Geophys. Res. 100,2817-2831. 

Knorr, W. and Heimann, M. (1995). Impact of drought stress and other factors on seasonal land biosphere CO2 exchange studied through an atmospheric tracer transport model, Tellus, Ser. B, 47, 471-489. 

Nemry, B., Francois, L., Warnant, P., Robinet, R. and Gerard, J.-C. (1996). The seasonality of the CO2 exchange between the atmosphere and the land biosphere A study with a global mechanistic vegetation model, /. Geophys. Res. 101, 7111-7125. 

Oechel, W.D. Collins, N.J. (1973). Seasonal patterns of CO2 exchange in bryo-phytes at Barrow, Alaska. In Primary Production and Production Processes, ed. L.C. Bliss and F.E. Wielogolaski, pp. 197-203. Stockholm Wenner-Gren Center. 

Taylor, R.J. Pearcy, R.W. (1976). Seasonal patterns in the CO2 exchange characteristics of understorey plants from a deciduous forest. Canadian Journal of Botany, 54, 1094-1103. 

Some studies, including more prominent ones (Reganold et al. 1993, Mader et al. 2002), have repeatedly shown a clearly positive impact of the biodynamic method on soil structure, enzyme activities, CO2 exchange and earthworm populations (Koepf 1993, Goldstein 2000). However, there are also studies that were not able to show such results (Carpenter-Boggs ef al. 

Co2 + -exchanged faujasite zeolite is a unique heterogeneous catalyst for liquid-phase epoxidation using 02 [45]. This catalyst is active only for styrene, and the conversion and yield of styrene oxide were 65 and 45%, respectively. The TON, based on Co ions, reached 12. The Co2+ ions, located in supercages, are thought to cause activation of 02 for epoxidation. 

Table 3.4. Annual budget of CO2 exchange with the atmosphere for water bodies of the Arctic Basin and northern seas (106 tC/yr).

Case 2. The raindrop falls on a limestone rock and comes to equilibrium with calcite, while remaining in equilibrium with the PCO2 of the atmosphere. This process results in dissolution of the rock, and addition of calcium and alkalinity to the raindrop. The knowns are Pc02> the initial composition of the solution, and that it must be in equilibrium with calcite. In this case, as in all others, electroneutrality must apply, but mass balance will not because of CO2 exchange with the atmosphere. First the equations will be written for calcium. 

Einhellig, F. A., Rice, E. L., Risser, P. G., and Wender, S. FI. 1970. Effects of scopoletin on growth, CO2 exchange rates, and concentration of scopoletin, scopolin, and chlorogenic acids in tobacco, sunflower, and pigweed. Bull. Torrey Bot. Club 97, 22-33... 

Larmola, T., Aim, J., Juutinen, S., Martikainen, P. J. Silvola, J. (2003). Ecosystem CO2 exchange and plant biomass in the littoral zone of a boreal eutrophic lake. 

For CO2 exchange, E in Equation 8.29 can be replaced by - c, I can be replaced by Jco2> and i can be replaced by Upon moving the resistance terms to the right-hand side of the equation, we thus obtain... 

Goulden M. L. and Crill P. M. (1997) Automated measurements of CO2 exchange at the moss surface of a black spruce forest. Tree Physiol. 17, 537-542. 

The dynamics of canopy-scale net fluxes of water and CO2 exchanged between vegetation and the atmosphere are routinely measured today with micrometeorological methods (e.g., with eddy covariance www.daac.ornl.gov/FLUXNET/ fluxnet.html). Combining these methods with isotopic measurements allows to partition a net flux into its gross flux components. The approach here is similar to that used on the global scale to... 

Flanagan L. B. and Varney G. T. (1995) Influence of vegetation and soil CO2 exchange on the concentration and stable oxygen-isotope ratio of atmospheric CO2 within a Pinus-resinosa canopy. Oecologia 101(1), 37-44. 

Inoue H. andSugimura Y. (1985) Carbon isotopic fractionation during the CO2 exchange process between air and seawater under equilibrium and kinetic conditions. Geochim. Cosmo-chim. Acta 49(11), 2453-2460. 

Ito A. (2003) A global-scale simulation of the CO2 exchange between the atmosphere and the terrestrial biosphere with a mechanistic model including stable carbon isotopes, 1953-1999. Tellus 55B, 596-612. 

Several attempts have been made to model these processes. Taylor and Fox (1996) studied the Waimakariri River in New Zealand. They modeled equilibrium of DIC with atmospheric CO2 using a chemical mass-balance model that accounts for the kinetics of CO2 equilibration between the aqueous and gas phase. Their results show that the measured 5 C values of the river water cannot be explained solely by equilibrium with atmospheric CO2, and that an addition of biogenic CO2 is necessary to account for the measurements. While their model represents a step forward in kinetic considerations of atmospheric CO2 exchange in river systems, their model does not account for DIC uptake by phytoplankton via photosynthesis, which would cause biological recycling and increases in 6 C of the residual riverine DIC pool. 

Boutin J. and Etcheto J. (1995) Estimating the chemical enhancement effect on the air-sea CO2 exchange using the ERS-1 scatterometer wind speeds. In Air-Water Gas Transfer (eds. B. Jahne and E. C. Monahan). AEON Verlag and Studio, Hanau, pp. 827-841. 

---