申論題

(5) (10 pts) Plcase describe in dctail how the atmospheric composition changed, starting from the Earth formed to now.
6 Table A lists the major redox processes occurring in the sediments and their redox potential (, in volt) at 25 C. I atmi, unit activity, and pH = 7. In the ecosystemn, animals and microbes usually perform respiration through the oxidation of carbohydrates to get energy and release CO₂. Dependent on the environment, diflerent proces sses will be performed.

(b)(10 pts) Below the surface (anoxic(缺氧)conditions), other respiration processes, such as denitrification, sulfate reduction, and methanogenesis, might become significant. Please write the overall reaction for denitrification and sulfate reduction, and calculate AE°(w), respectively.