Nutrients OTHER THAN carbon are introduced into ecosystems in the open ocean by:
a. viruses
b. They aren't, nutrient cycling in the open ocean relies solely on recycling of dissolved organic matter
c. primary producers such as phytoplankton
d. primary producers such as plants
2. A "bloom" of aerobic chemoorganoheterotroph growth is more likely in smaller freshwater environments (rivers and lakes) than in the open ocean. Which of the following is the most likely explanation as to why this is true?
a. more organic carbon is available in freshwater environments
b. more oxygen may be available in freshwater environments
c. the pH is more likely neutral in freshwater conditions
d. oxygen depletion causes die-offs in freshwater, but not in the ocean
3. Which of the following statements is true regarding aquatic environments?
a. microbes are critical in recycling because they utilize dissolved organic matter, then they themselves are consumed by "higher" organisms
b. microbes are less likely to be important producers of organic carbon in the open ocean than freshwater environments
c. microbes in the benthic (deep) zone are most likely producers
d. microbes are not critical in recycling
4. A Photoheterotrophic metabolism is useful in the open ocean because:
a. It allows microbes to generate cellular macromolecules without sacrificing energy yield
b. It makes use of light, rather than complete glucose breakdown, to produce energy
c. It reduces the amount of CO2 (a harmful greenhouse gas) released back into the environment relative to chemoorganotrophic organisms
d. all of the above