Carbon cycles, global

Gombert, P. 2002. Role of karstic dissolution in global carbon cycle. Global and Planetary Change, 33, 177-184. 

Schimel, D. S. (1995). Terrestrial ecosystems and the carbon cycle. Global Change Biol. 1, 77-91. 

Reimers, C. E., Jahnke, R. A., and McCorkle, D. C. (1992). Carbon fluxes and burial rates over the continental slope off California with implications for the global carbon cycle. Global Biogeochem. Cycles. 6, 199-224. 

Stallard R. F. (1998) Terrestrial sedimentation and the carbon cycle coupling weathering and erosion to the carbon cycle. Global Biogeochem. Cycles 12, 231-257. 

Broecker W. S. (2001) A Ewing Symposium on the contemporary carbon cycle. Global Biogeochem. Cycles 15, 1031-1032. 

Bender, M., Ellis, X, Tans, R, Francey, R., and Lowe, D. (1996). Variability in the O2/N, ratio of southern hemisphere air, 1991-1994—Implications for the carbon cycle. Global Biageachem. Cycles 10, 9-21. 

Keeling, R. E, Najjar, R. R, Bender, M. L, and Tans, P. P. (1993). What atmospheric oxygen measurements can tell us about the global carbon cycle. Global Biogeochein Cycles 7, SI-67. 

Carbon. Most of the Earth s supply of carbon is stored in carbonate rocks in the Hthosphere. Normally the circulation rate for Hthospheric carbon is slow compared with that of carbon between the atmosphere and biosphere. The carbon cycle has received much attention in recent years as a result of research into the possible relation between increased atmospheric carbon dioxide concentration, most of which is produced by combustion of fossil fuel, and the "greenhouse effect," or global warming. Extensive research has been done on the rate at which carbon dioxide might be converted to cellulose and other photosyntheticaHy produced organic compounds by various forms of natural and cultivated plants. Estimates also have been made of the rate at which carbon dioxide is released to soil under optimum conditions by various kinds of plant cover, such as temperature-zone deciduous forests, cultivated farm crops, prairie grassland, and desert vegetation. 

The harmful effects of air pollutants on human beings have been the major reason for efforts to understand and control their sources. During the past two decades, research on acidic deposition on water-based ecosystems has helped to reemphasize the importance of air pollutants in other receptors, such as soil-based ecosystems (1). When discussing the impact of air pollutants on ecosystems, the matter of scale becomes important. We will discuss three examples of elements which interact with air, water, and soil media on different geographic scales. These are the carbon cycle on a global scale, the sulfur cycle on a regional scale, and the fluoride cycle on a local scale. 

Figure 8.1 Diagrammatic model of the global carbon cycle. Questions marks indicate that no estimates are available. Figures are in units of lO tonnes of contained carbon but estimates from various sources sometimes differ by factors of 3 or more. The diagram is based on one by B. Bolin modified to include more recent data. ...

Schlamdinger, B., and Marland, G. (1996). The Role of Forest and Bioenegy Strategies in the Global Carbon Cycle. Biomass and Biocncrgy 10(5/6) 275-300. 

Up to this point, we have focused on aqueous equilibria involving proton transfer. Now we apply the same principles to the equilibrium that exists between a solid salt and its dissolved ions in a saturated solution. We can use the equilibrium constant for the dissolution of a substance to predict the solubility of a salt and to control precipitate formation. These methods are used in the laboratory to separate and analyze mixtures of salts. They also have important practical applications in municipal wastewater treatment, the extraction of minerals from seawater, the formation and loss of bones and teeth, and the global carbon cycle. 

The Table of Contents for this collection will facilitate this discussion. Notice that the papers are grouped into the categories of Atmospheric, Aquatic and Terrestrial Components, Global Carbon Cycle and Climate Change, and Global Environmental Science Education. The reader may want to consider the various chemical species studied in each paper. Next, the reader may wish to group the papers by whether they address the source or the receptor, the transport or transformation processes for the chemical species. Finally, the reader needs to establish the time scales and the spatial resolution used. 

POST ET AL. Climatic Feedbacks in the Global Carbon Cycle... 

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 magnitude and fate of coastal-zone biological production is a major unknown in the global carbon cycle. Since river nutrient flux into these regions may be altered with C02-induced climate change, it is important that generation and fate of coastal-zone production be better understood. 

The research detailed in previous sections outlines productive steps toward increased certainty in global quantification of the effects that climate has on carbon cycle processes. Presented here is a short summary of future research directions. 

---