Flashcards in Exam 3 Deck (52)
Study of how biogeochemical cycles can be linked to the global climate.
Sum of the microbial and chemical processes that drive the flow of elements between sediments, waters, and the atmosphere.
Microbes make profound changes in which ecosystems?
Freshwater and marine systems
Development of rich soils
Why is a gaseous component important?
Because it goes out into the air and is out of reach/out of the system. One needs assimilation to get it back into the system.
Reduction/Oxidation Potential of Environments
Measure of the tendency of a chemical compound to accept electrons and become reduced.
What is the oxidation state of any given habitat?
A function of the redox state of the environment.
What plays a critical role in determining the biogeochemical flux of elements?
Oxidation state/the redox state of the environment.
Which major elements have a gaseous component?
C, N, and S.
Which major elements do NOT have a gaseous component?
Fe and P
Reduced form of the C cycle
Reduced form of the N cycle
NH4 (ammonium)... and organic N
Reduced form of the S cycle
H2S (hydrogen sulfide)... and organic SH groups
Reduced form of the P cycle
HA! There is none!
Reduced form of the Fe cycle
Fe2+ (ferrous iron)
What can the reduced forms of cycles be used as?
e- DONORS! :)
Which cycle always has its intermediate oxidation state forms present in a maximally oxidized state?
P cycle xD
What can the oxidized forms of cycles be used as?
Oxidized form of the C cycle
Oxidized form of the N cycle
Oxidized form of the S cycle
Oxidized form of the Fe cycle
Fe3+ (ferric iron)
Oxidized form of the P cycle
What does -854kJ/reaction for the ΔG tell you about the the sediment environment?
Most likely aerobic respiration, in oxic conditions, and uses O2 as the TEA.
What does -801kJ/reaction through -35kJ/reaction for the ΔG tell you about the the sediment environment?
Most likely ANOXIC conditions.
What does -801kJ/reaction for the ΔG tell you about the the sediment environment?
Denitrification. Anoxic. Nitrate (NO3-) as TEA.
What does -337kJ/reaction for the ΔG tell you about the the sediment environment?
Fe(III) (ferric) reduction. Anoxic.
What does -48kJ/reaction for the ΔG tell you about the the sediment environment?
Sulfate reduction. Anoxic.
What does -35kJ/reaction for the ΔG tell you about the the sediment environment?
What does the Carbon Cycle slide say about "oxidized e.g."?
CO and CO2