Biogeochemistry 1

Question 1

What are the three main processes/timescales that control the atmospheric composition of CO2? What are the corresponding reservoirs of carbon for each of these processes/timescales?

Answer 1

1) geology (millions of years)
2) ocean circulation (thousands of years)
3) ecosystem ecology and ocean chemistry (days to hundreds of years)

Question 2

At the multi-million year timescale, the balance of what two processes determines the abundance of CO2 in the atmosphere?

Answer 2

carbonate in rocks

and organic carbon in rocks

Question 3

400 million years ago, the atmospheric CO2 was 10-15 times higher than today. By 350 Mya, it was within factors of 2-3 of present day. What is believed to have caused the big draw down and how?

Answer 3

PLANTS

Question 4

Define these terms:

pedosphere

lithosphere

hydrosphere

biosphere

Answer 4

pedosphere - soils

lithosphere - WHERE CARBON IS SEQUESTERED IN CARBONATE AND ORGANIC CARBON IN ROCKS, solid earth

hydrosphere - where carbon is stored in the ocean and fresh water

biosphere - soil carbon, atmospheric, living organic matter, and surface ocean water

Question 5

Why does atmospheric CO2 not increase by the same amount of CO2 being added by fossil fuel combustion?

Answer 5

because the ocean is acting as a carbon sink right now and is capturing about half of what we emit.

Question 6

What is ecosystem ecology? What is biogeochemistry?

Answer 6

ecosystem ecology is the study of interactions among organisms and their physical environment as an integrated system. Biogeochemistry is the study of the interactions between organisms and geologic processes.

Question 7

What is the simplified net chemical reaction known as photosynthesis? What is the net chemical reaction known as respiration? What is the difference between the two?

Question 8

Define the following terms, and be able to relate them to each other mathematically:

a) Gross Primary Production (GPP)
b) Autotrophic Respiration (R_auto)
c) Net Primary Production (NPP)
d) Heterotrophoc Respiration (R_het)
e) Net Ecosystem Production (NEP)
f) Ecosystem Respiration (R_eco)

Question 9

What are some of the most important controls on NPP?

Answer 9

GPP-Respiration=NPP

water

temperature

soil quality

Question 10

What does it mean for NPP to be “limited” by factor X (for example, nitrogen)?

Answer 10

It means that if you add more of that limiting factor into the system, then you will get more NPP

Question 11

NPP is the fundamental biological process by which CO2 enters terrestrial ecosystems and is stored as organic carbon. What is the basic process by which organic matter leaves terrestrial ecosystems, returning to CO2?

Answer 11

autotrophic and heterotropich respiration