Answer 1 of the 3 questions listed below. Please indicate cl…
Answer 1 of the 3 questions listed below. Please indicate clearly which question (1,2, or 3) you are answering. Optional: answer one additional question for up to 8 points of extra credit 1. Distinguish between the short-term biologically-driven global carbon cycle vs. the long-term rock carbon cycle. Outline the basic processes involved and the time scales on which they play out. If either of the two were to be able to help offset increased atmospheric CO2 due to human activity, which would it be (hint: how would increased delivery of organic carbon to the deep ocean, or storage of organic carbon in terrestrial soils) be expected to influence the size of atmospheric CO2 pool? 2. List six major organic carbon oxidation reactions in order of decreasing free energy release, which corresponds to their sequence in terms of “biogeochemical zonation”. How is this phenomenon involved in controlling the production of methane in marine sediments that under the appropriate condition can lead to methane hydrate formation? 3. Where in the marine environment does most organic carbon (and pyrite) burial take place? Why (in simple terms) is that the case? (hint: think about the relationships between primary production, water depth, organic carbon deposition, and the impact of sediment O2 availability on organic carbon preservation).