Bacteria are major players in biogeochemical cycles. Give examples of different environments and the relative abundance of bacteria in each. Describe the way in which the environment will determine the rate at which nutrients become available through impacts on bacteria.(200 words)

Discuss two means by which mineral sulfur is deposited from the atmosphere. Describe three inputs of sulfur into the atmosphere. (75 words)

Describe how atmospheric carbon dioxide levels fluctuate daily, seasonally, and geographically. Explain why such fluctuation occurs. (75 words)