Biogeochemical cyclesBiogeochemical cycles& Mineralisation

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Elemental cycles: C, N, S, P, Fe, Mn

Biomass substitute for oil

Fig. 27.1 Macrobiogeochemistryg g y

Fi 27 2 C b lFig. 27.2 Carbon cycle

Fig. 27.3Influence of oxygen on degradation of organic matter.

Fig. 27.4 Nitrogen cycle

Nodules on the roots of Legume plantg p

Rhizobium species live in the nodules fi N D d hi bi Nto fix N2. Dead rhizobia are N-source

for plant to synthesize amino acids.

N2 + 3H2 → 2 NH3

Nitrogenase, ATP, Mo, Fe165 · 106 ton N/yr

Haber-Bosch process:p40 · 106 ton N/yr

Biological nitrogen fixationg g• Symbiotic kg N/ha·yr

h bRhizobium 20 – 500clover, sojabeans, pea, luzern

Actinomyceter 40 – 500yalder, buckthorn, myrtle, avens

• Non-symbioticAzotobacter Clostridium 0 2Azotobacter, Clostridium 0.2Bluegreen algae 10 - 20

Fig 27 6 Sulfur cycleFig. 27.6 Sulfur cycle

Fig. 27.5 Phosphorus cycle

Fig. 27.7 Fe cycle

Fig 27 8 Manganese cycleFig. 27.8 Manganese cycle

Fig. 27.9 The Mercury cycle

Fig. 27.10 Microenvironments

Role of microorganisms in flow of organic carbon and CO2