Sample Q4 answers

1. C

2. A

3. C (“Bucky Balls”, or more formally, fullerenes)

4. B

5. B

6. D (bicarbonate is a dissolved carbon species as you would expect in ocean WATER; CO₃⁼ and CO_2dissolved are also very important carbon species in ocean water)

7. C

8. C

9. D (“land-use change” is conversion of land, such as deforestation in order to provide land for agriculture or grazing, which results in release of CO2, just as mechanisms A and B)

10. D

11. D

12. D

13. C

14. D

15. A (see classnotes for March 24, look at “Global maps” link)

16. atmosphere, biosphere, oceans, lithosphere, soils

17. Generally it is conversion of natural ecosystems to other uses such as urban areas (urbanization) or transportation (roads) or reservoirs behind dams (energy, water storage, etc) or agriculture. Deforestation would be an example, which involves conversion of land from forest to agriculture or grazing (or maybe even cities). Also natural grasslands may be changed to agriculture. Usually such changes result in loss of carbon from the ecosystems, but in some cases such as the abandonment of farmland carbon can be increased.

18. Living and Dead organic matter in tropical forest biomes is dominated by living plant parts (roots, stems, trunks, leaves) with a smaller fraction of dry matter in dead material (litter and soil), whereas dry matter in grasslands is overwhelmingly in dead material, with a small fraction in living plant parts (review http://www.ltrr.arizona.edu/nats101/DryMatter3-26-08.pdf)

19. Competition for light resources tends to be much greater on land than in water, and on land the best way to compete is to grow fast and tall, above you neighbors. Consequently, a very high investment in plant structural components on land is needed (trunks, stems) as wood, compared to marine biosphere where such structural components are not needed.

20. Non-native species that have entered an area (accidentally or purposely) with the result that they become established and compete with (maybe outcompete) native species. See your notes and my ClassNotes from March 29

21. Dominance of photosynthesis in spring and summer draws down CO2 from the atmosphere, and dominance of respiration returns CO2 to the atmosphere in Fall and Winter. (“seasonal biosphere” is key to where the effect is greatest, as related to question #1).

22. embayment between river and open ocean (like Chesapeake Bay and San Francisco Bay), where salinity is quite variable (usually low near surface and high near bottom). It will be affected by tides, and many commercial fish species will spend at least a portion of their life in these highly productive areas. (coral reefs are the “rain forests of the seas”)

23. warmer temperatures could promote geographical expansion of malaria, but reduction of precipitation at lower latitudes could inhibit spread of malaria

24. See March 22 classnotes and Mackenzie

25. NPP=GPP-respiration (see your Mar 24 notes and classnotes and Mackenzie)

26. C3 grasses are “cool-season” grasses, and C4 grasses are “warm season” grasses. Invasive C3 grasses may gain a competitive advantage as atmospheric CO2 increases. [Note, many plants worldwide such as trees are C3 plants, but they are not grasses]