1-C (respiration is flux, not pool)

2-D

3-C

4-D (ethanol can be produce from corn, so we can "grow" it every year)

5-C

6-C (high latitude, N. Hemisphere)

7-B

8-D

9-A

10-A

11-D (HCO3- is the most abundant dissolved carbon species in the ocean, although there are other dissolved species including CO3--, and dissolved CO2)

12-D

12. There is a relatively “new” large flux from lithosphere to atmosphere in the amount of about 6 GtC per year currently from fossil-fuel combustion and calcining. This flux only started about 200 years ago with the dawn of the Industrial Revolution. This extra 6 GtC is then taken up by several sinks, some of which we are certain (that retained by the atmosphere and that which is going into the ocean), and others of which we are less certain (biosphere, soils)

13. Photosynthesis is the main component of primary production, and it requires the C from CO2 as a primary nutrient, but productivity also requires other nutrients such as N. Thus primary production is a major sink for N and C in their respective biogeochemical cycles.

14. 70/3.5= 20 years ("rule of 70")

15. immigration (legal or illegal)

16. conversion of natural ecosystems to other uses such as urban areas (urbanization) or transportation (roads) or reservoirs behind dams (energy, water storage, etc) THIS WILL NOT BE ON QUIZ 4, BUT WE WILL SHORTLY COVER IT FOR QUIZ 5