Carbon temporal trends

Current data on atmospheric C02 concentrations and temporal trends as well as those of other trace gases are available from the U.S. Department of Energy s Carbon Dioxide Information Analysis Center (CDIAC) (World Wide Web page is http //cdiac.esd.ornl.gov/cdiac). CDIAC also has available a number of additional data packages on global change issues such as trends in temperature and precipitation. 

Within some individual samples, including both early and late calcites. Mg and Fe display a positive covariation that may be related to zoning (Fig. 6). If analogy can be made to the between-sample covariation, it is possible that this zoning relates to a temporal trend of relatively high contents of both Mg and Fe in early precipitates and lower concentrations in later ones however, there is no direct petrographic evidence to support the existence of this trend. Similar positive covariations between Mg and Fe have been reported in other studies of carbonate cementation in sandstones (e.g. Prosser et al., 1993 Milliken et ai, this volume). 

Although Equations (8) and (9) fail to provide timescales for transformation of 5c and require that the oceans are well-mixed, they accurately provide the seme (positive or negative) of long-term temporal trends in 5c due to variation in other factors, and this is often the more interesting result. First-order approximations of the expected isotopic response of marine 5 C values to change in carbon input and output functions can be... 

Grieve, I. C. 1991b. Dissolved organic carbon trends in small streams, land use effects and models of temporal variation. In Sediment and Stream Water Quality in a Changing Environment Trends and Explanation. Proceedings of the Vienna Symposium, August, 1991. IAHS Publication, No. 203, pp. 201-208. 

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