Respiration fermentation methanogenesis

The anaerobic decomposition of organic matter by fermentation, methanogenesis (methane formation) and sulfate respiration is exemplified in Table 3.2. 

When SO42- is depleted and methanogenesis is the dominant form of anaerobic respiration, it can proceed through either of the following two pathways fermentation or C02 reduction. 

Finally, after all of the sulfate is consumed, organic material can be fermented into methane and carbon dioxide in the process of methanogenesis. Fermentative reactions, of which there are many examples in the environment, differ from respiration in that they do not change the average oxidation state of carbon. The reaction for methanogenesis is... 

Respiration Photosynthesis Denitrification Nitrification Ammonia volatilization Sulfate reduction Fermentation Nitrogen fixation Methanogenesis Phosphate reduction... 

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