Endogenic carbon cycle

If we assume that the entire carbon cycle is maintained in a steady state condition (Siever, 1968 Garrels and Mackenzie, 1972 Garrels et al., 1975, 1976), it follows that the amounts of carbon present at any time in the biosphere, atmosphere and hydrosphere remain relatively small. Thus this carbon circulates at relatively high rates, and has a short residence time within each of these three pools. Most of the carbon is stored in sediments and is thus removed from the exogenic circulation for millions of years. This carbon returns slowly via the endogenic cycle (Fig. 2.1.5). 

Fig. 2.1.3. Schematic presentation of the exogenic and endogenic cycling of inorganic carbon.

Fig. 2.1.5. The relative cycling frequency of an average carbon atom within the atmosphere, biosphere and hydrosphere (exogenic cycles) relative to the cycling in the litho-spere (endogenic cycles).

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