Carbon dioxide biogeochemical cycle

An important example of non-linearity in a biogeochemical cycle is the exchange of carbon dioxide between the ocean surface water and the atmosphere and between the atmosphere and the terrestrial system. To illustrate some effects of these non-linearities, let us consider the simplified model of the carbon cycle shown in Fig. 4-12. Ms represents the sum of all forms of dissolved carbon (CO2, H2CO3, HCOi" and... 

C. J. and Schloss, A. L. (1997). Equilibrium responses of global net primary production and carbon storage to doubled atmospheric carbon dioxide Sensitivity to changes in vegetation nitrogen concentration, Global Biogeochem. Cycles 11,173-189. 

Randerson, J. T., Thompson, M. V., Conway, T. J., Fung, I. Y. and Field, C. B. (1997). The contribution of terrestrial sources and sinks to trends in the seasonal cycle of atmospheric carbon dioxide. Global Biogeochem. Cycles 11,535-560. 

Andrew Dickson (Chair) is an Associate Professor-in-Residence at the Scripps Institution of Oceanography. His research focuses on the analytical chemistry of carbon dioxide in sea water, biogeochemical cycles in the upper ocean, marine inorganic chemistry, and the thermodynamics of electrolyte solutions at high temperatures and pressures. His expertise lies in the quality control of oceanic carbon dioxide measurements and in the development of underway instrumentation for the study of upper ocean biogeochemistry. Dr. Dickson served on the NRC Committee on Oceanic Carbon. He is presently a member of the IOC C02 Advisory Panel and of the PICES Working Group 13 on C02 in the North Pacific. 

Lafleur, P. M., Roulet, N. T., Bubier, J. L., Frolking, S., and Moore, T. R. (2003). Interannual variability in the peatland-atmosphere carbon dioxide exchange at an ombrotrophic bog. Global Biogeochem. Cycles 17,1036. 

Raich, J W., and Potter, C. S. (1995). Global patterns of carbon dioxide emissions from soils. Global Biogeochem. Cycles 9(1), 23-36. 

Table 3.3. Reservoirs and fluxes of carbon as CO2 in the biosphere in a simulation model of the global biogeochemical cycle of carbon dioxide as shown in Figure 3.6.

On the whole, when synthesizing a global model of the C02 biogeochemical cycle, the unit to simulate that part of the cycle spent in the ocean must describe how the ocean carbonate system works. Alekseev et al. (1992), analyzing the system C02 IICO, COj and the distribution of pH values in ocean waters, discovered that more than 80% of dissolved carbon dioxide is in the form of hydrocarbonate ion of HC03. This means that when synthesizing a model of the ocean carbonate system only the first stage of the dissociation of carbonic acid can be reliably considered. As a result, the flux of C02 dissolved in the upper layer of the ocean can be calculated by the formula... 

It is clear that the observed increase in carbon dioxide, methane, and nitrous oxide in the atmosphere cannot be explained by anthropogenic causes only. We need to bear in mind that the changeability of GHG biogeochemical cycles is a complex function of numerous parameters controlled by the NSS. Unfortunately, there is no reliable information about the correlations between many of them. This fact is admitted by experts in IPCC (2007). 

Krapivin, V.F. (1999a) Greenhouse effect and global biogeochemical carbon dioxide cycle. Problems of Environment and Natural Resources, 12, 2-16 [in Russian]. 

Studies of the modem global biogeochemical cycle of carbon form one basis for understanding the geologic history of atmospheric CO2. In turn, these investigations of the history of carbon dioxide in the atmosphere provide knowledge that can be used to interpret the future of atmospheric CO2 levels and... 

In the last 150 years the anthropogenic emission of sulfur has increased dramatically, primarily due to combustion processes [1]. In the 1950s anthropogenic emission surpassed natural emission and the atmospheric sulfur cycle is one of the most perturbed biogeochemical cycles [1,2]. The oceans are the largest natural source of atmospheric sulfur emissions, where sulfur is emitted in a reduced form, predominantly as dimethyl sulfide (DMS) and to a much lesser extent carbonyl sulfide (OCS) and carbon disulfide (CS2) [3]. Ocean emitted DMS and CS2 are initially oxidised to OCS, which diffuses through the troposphere into the stratosphere where further oxidation to sulfur dioxide (SO2), sulfur trioxide (SO3) and finally sulfuric acid (H2SO4) occurs [1-4]. 

Barcelos e Ramos, J., Biswas, H., Schrdz, K. G., LaRoche, J., and RiebeseU, U. (2007). Effect of rising atmospheric carbon dioxide on the marine nitrogen fixer Trichodesmium. Glob. Biogeochem. Cycles... 

Moore, J. K., Abbott, M. R., Richman, J. G., Nelson, D. M. (2000). The Southern Ocean at the last glacial maximum A strong sink for atmospheric carbon dioxide. Global Biogeochem. Cycles 14, 455-475. 

Bowling D. R., Baldocchi D. D., and Monson R. K. (1999a) Dynamics of isotopic exchange of carbon dioxide in a Tennessee deciduous forest. Global Biogeochem. Cycles 13(4), 903-922. 

Buitenhuis E. T., van der Wal P., and de Baar H. J. W. (2001) Blooms of Emiliania huxleyi are sinks of atmospheric carbon dioxide a field and mesocosm study derived simulation. Global Biogeochem. Cycles 15, 511-5%1. 

Sanderson M. G. (1996) Biomass of termites and their emissions of methane and carbon dioxide a global database. Global Biogeochem. Cycles 10, 543-557. 

In the atmosphere CO2 is affected by processes that operate at different time scales, including interaction with the silicate cycle (see Chapter 2), dissolution in the oceans, and annual cycles of photosynthesis and respiration (see also Section 3). The relative effect of these processes is described below in the consideration of the whole carbon biogeochemical cycle and environmental aspects of biogeochemistry. Here, it is important to note that carbon dioxide is not reactive with other atmospheric species its MRT is 3 years (Figure 4). This value is largely determined by exchange with seawater (see Section 2). 

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