Zone model, fermentation

Rates of methane production via both acetate fermentation and C02 reduction were directly measured with radiotracer techniques in the sulfate-depleted sediments of Saanich and Princess Louisa Inlets (Kuivila etal., 1990). Comparison of measured and modeled rates suggests that these two pathways account for the majority of methane produced below the sulfate reduction zone in the sediments of both the basins. Prior aerobic degradation of the organic matter has little influence on the pathways of methane production. 

A less ideal variation of the mixed Type 1 and Type 3 environments is shown in the conceptual model in Figure 23.1.8. An extended TCE and 1,2-DCE plume results because insufficient fermentable carbon results in an anaerobic zone which is too short for complete biodegradation. Therefore, TCE extends well into the aerobic zone where no biodegradation occurs. A long DCE plume also extends into the aerobic zone, indicating in-... 

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