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Flashcards in Exam 3 Deck (52)
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1

Environmental microbiology

Study of how biogeochemical cycles can be linked to the global climate.

2

Biogeochemical cycling

Sum of the microbial and chemical processes that drive the flow of elements between sediments, waters, and the atmosphere.

3

Microbes make profound changes in which ecosystems?

Atmosphere
Freshwater and marine systems
Development of rich soils

4

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.

5

Reduction/Oxidation Potential of Environments

Measure of the tendency of a chemical compound to accept electrons and become reduced.

6

What is the oxidation state of any given habitat?

A function of the redox state of the environment.

7

What plays a critical role in determining the biogeochemical flux of elements?

Oxidation state/the redox state of the environment.

8

Which major elements have a gaseous component?

C, N, and S.

9

Which major elements do NOT have a gaseous component?

Fe and P

10

Reduced form of the C cycle

CH4

11

Reduced form of the N cycle

NH4 (ammonium)... and organic N

12

Reduced form of the S cycle

H2S (hydrogen sulfide)... and organic SH groups

13

Reduced form of the P cycle

HA! There is none!

14

Reduced form of the Fe cycle

Fe2+ (ferrous iron)

15

What can the reduced forms of cycles be used as?

e- DONORS! :)

16

Which cycle always has its intermediate oxidation state forms present in a maximally oxidized state?

P cycle xD

17

What can the oxidized forms of cycles be used as?

e- acceptors.

18

Oxidized form of the C cycle

CO2

19

Oxidized form of the N cycle

NO3- (nitrate)

20

Oxidized form of the S cycle

SO4 2-

21

Oxidized form of the Fe cycle

Fe3+ (ferric iron)

22

Oxidized form of the P cycle

PO4- (phosphate)

23

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.

24

What does -801kJ/reaction through -35kJ/reaction for the ΔG tell you about the the sediment environment?

Most likely ANOXIC conditions.

25

What does -801kJ/reaction for the ΔG tell you about the the sediment environment?

Denitrification. Anoxic. Nitrate (NO3-) as TEA.

26

What does -337kJ/reaction for the ΔG tell you about the the sediment environment?

Fe(III) (ferric) reduction. Anoxic.

27

What does -48kJ/reaction for the ΔG tell you about the the sediment environment?

Sulfate reduction. Anoxic.

28

What does -35kJ/reaction for the ΔG tell you about the the sediment environment?

Methanogenesis. Anoxic.

29

What does the Carbon Cycle slide say about "oxidized e.g."?

CO and CO2

30

What does the cycle begin with?

Carbon fixation