Carbon cycle ocean/atmosphere

Hooss, G., Voss, R., Hasselmann, K., Maier-Reimer, E., and Joos, F. (2001). A nonlinear impulse response model of the coupled carbon cycle-ocean-atmosphere climate system. Clim. Dyn. (in press). 

In recent years innumerable publications have dealt with the natural carbon cycle and its alteration by human activities. Some summary works of interest in this chapter are Atmospheric Carbon Dioxide and the Global Carbon Cycle (ed. Trabalka, 1985), The Carbon Cycle and Atmospheric CO2 Natural Variations, Archean to Present (eds. Sundquist and Broecker, 1985), Chemical Cycles in the Evolution of the Earth (eds. Gregor, Garrels, Mackenzie, and Maynard, 1988), History of the Earth s Atmosphere (Budyko, Ronov, and Yanshin, 1985), and The Chemical Evolution of the Atmosphere and Oceans (Holland, 1984). The interested reader is referred to these volumes for further discussion of material presented here. 

Curry W.B. and Lohmann G.P. (1985) Carbon deposition rates and deep water residence time in the equatorial Atlantic Ocean throughout the last 160,000 years. In The Carbon Cycle and Atmospheric CO2 Natural Variations Archean to Present (eds. E.T. Sundquist and W.S. Broecker), pp. 285-301. Amer. Geophys. Union, Washington, D.C. 

Volk, T., and HofFert, M. I. (1985). Ocean carbon pumps analysis of relative strengths and efficiencies on ocean-atmospheric pC02 changes. In The Carbon Cycle and Atmospheric C02, Natural Variation. (Sundquist, E. T., and Broecker, W. S., eds.). Archen to Present, Geophysical Monograph Series 32. American Geophysical Union, pp. 99—120. 

Shackleton N. J. (1985) Oceanic carbon isotope constraints on oxygen and carbon dioxide in the Cenozoic atmosphere. In The Carbon Cycle and Atmospheric CO2 Natural Variations—Archean to Present, Chapman Conference on Natural Variations in Carbon Dioxide and the Carbon Cycle. AGUMonogr. 32, 412-417. 

Figure 3 Results from a simple three-box ocean carbon cycle model, (a) The physical circulation and modeled radiocarbon (A C) values, (b) The model biogeochemical fields, ocean DIG, and phosphate PO4) and atmospheric pCOa. From Toggweiler JR and Sarmiento JL, Glacial to inter-glacial changes in atmospheric carbon dioxide The critical role of ocean surface waters in high latitudes, The Carbon Cycle and Atmospheric CO2. Natural Variations Archean to Present, Sundquist ET and Broecker WS (eds.), pp. 163-184, 1985, Copyright [1985]. American Geophysical Union. Adapted by permission of American Geophysical Union.

Toggweiler JR and Sarmiento JL (1985) Glacial to interglacial changes in atmospheric carbon dioxide The critical role of ocean surface waters in high latitudes. In Sundquist ET and Broecker WS (eds.) The Carbon Cycle and Atmospheric CO2 Natural Variations Archean to Present, pp. 163-184. Washington, DC American Geophysical Union. 

Considerable efforts to elucidate carbon cycle in atmosphere-ocean-solid earth system have been carried out since the pioneer work by Rubey (1951). Representative models on carbon cycle previously proposed are illustrated in Fig. 5.14 (Shikazono 1995). They are the following (l)-(4). 

Human interaction with the global cycle is most evident in the movement of the element carbon. The burning of biomass, coal, oil, and natural gas to generate heat and electricity has released carbon to the atmosphere and oceans in the forms of CO2 and carbonate. Because of the relatively slow... 

Like all matter, carbon can neither be created nor destroyed it can just be moved from one place to another. The carbon cycle depicts the various places where carbon can be found. Carbon occurs in the atmosphere, in the ocean, in plants and animals, and in fossil fuels. Carbon can be moved from the atmosphere into either producers (through the process of photosynthesis) or the ocean (through the process of diffusion). Some producers will become fossil fuels, and some will be eaten by either consumers or decomposers. The carbon is returned to the atmosphere when consumers respire, when fossil fuels are burned, and when plants are burned in a fire. The amount of carbon in the atmosphere can be changed by increasing or decreasing rates of photosynthesis, use of fossil fuels, and number of fires. 

Figure 1. Changes in global climate due to increased atmospheric CO2 will alter carbon cycle processes in land, continent margins, and oceans, which will in turn effect the atmospheric C02concentration. Processes that may have effects large enough to Eilter future projections of atmospheric CO2 are listed under their geographic region.

The most common way in which the global carbon budget is calculated and analyzed is through simple diagrammatical or mathematical models. Diagrammatical models usually indicate sizes of reservoirs and fluxes (Figure 1). Most mathematical models use computers to simulate carbon flux between terrestrial ecosystems and the atmosphere, and between oceans and the atmosphere. Existing carbon cycle models are simple, in part, because few parameters can be estimated reliably. 

Bjorkstrom, A. 1979. A model of CO2 interaction between atmosphere,oceans, and land biota. In The Global Carbon Cycle, Bolin, B. Degens, E. T. Kempe, S. Ketner, P., Eds. SCOPE 13 J Wiley Sons New York, NY, 1979 pp 403-457. 

Budgets and cycles can be considered on very different spatial scales. In this book we concentrate on global, hemispheric and regional scales. The choice of a suitable scale (i.e. the size of the reservoirs), is determined by the goals of the analysis as well as by the homogeneity of the spatial distribution. For example, in carbon cycle models it is reasonable to consider the atmosphere as one reservoir (the concentration of CO2 in the atmosphere is fairly uniform). On the other hand, oceanic carbon content and carbon exchange processes exhibit large spatial variations and it is reasonable to separate the... 

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... 

Rainwater and snowmelt water are primary factors determining the very nature of the terrestrial carbon cycle, with photosynthesis acting as the primary exchange mechanism from the atmosphere. Bicarbonate is the most prevalent ion in natural surface waters (rivers and lakes), which are extremely important in the carbon cycle, accoxmting for 90% of the carbon flux between the land surface and oceans (Holmen, Chapter 11). In addition, bicarbonate is a major component of soil water and a contributor to its natural acid-base balance. The carbonate equilibrium controls the pH of most natural waters, and high concentrations of bicarbonate provide a pH buffer in many systems. Other acid-base reactions (discussed in Chapter 16), particularly in the atmosphere, also influence pH (in both natural and polluted systems) but are generally less important than the carbonate system on a global basis. 

Baes, C. F., Bjdrkstrom, A. and MuIhoUand, P. J. (1985). Uptake of carbon dioxide by the oceans. In "Atmospheric Carbon Dioxide and the Global Carbon Cycle" (J. R. Trabalka, ed.). Report DOE/ ER-0239, US Department of Energy, Office of Energy Research, Washington, DC. 

Bjdrkstrom, A. (1979). A model of CO2 interaction between atmosphere, oceans, and land biota. In "The Global Carbon Cycle" (B. Bolin, E. T. Degens, S. Kempe, and P. Ketner, eds), pp. 403-457. Wiley, New York. 

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