Nutrient Cycling and Retention Test Bank Ch.19

Ecology, 8e (Molles)

Chapter 19 Nutrient Cycling and Retention

1) The largest reservoir of phosphorus in most ecosystems is phosphorus

A) in the atmosphere.

B) dissolved in water.

C) in rocks and sediments.

D) bound in animal tissues.

E) bound in plant tissues.

2) Phosphorus is an important constituent of

A) DNA.

B) bone tissue.

C) RNA.

D) ATP.

E) All of the choices are correct.

3) "Nitrogen fixation" refers to the conversion of

A) carbon compounds to nitrogen compounds.

B) nitrogen gas (N2) to ammonia (NH3).

C) ammonia (NH3) to nitrogen gas (N2).

D) ammonium (NH4+) to nitrate (NO3-).

E) ammonium (NH4+) to nitrite (NO2-).

4) Which of the following is NOT an agent of nitrogen fixation?

A) Mycorrhizal fungi

B) Cyanobacteria (blue-green algae)

C) Bacteria associated with legume roots

D) Lightning

E) Actinomycete bacteria associated with alder roots

5) "Nitrification" is the conversion of

A) carbon compounds to nitrogen compounds.

B) nitrogen gas (N2) to ammonia (NH3).

C) ammonium (NH4+) to nitrate (NO3-).

D) ammonia (NH3) to nitrogen gas (N2).

E) ammonium (NH4+) to nitrite (NO2-).

6) A major perturbation of the carbon cycle by human activity is associated with

A) release of carbon from carbonate rocks.

B) release of carbon from fossil fuel deposits.

C) removal of carbon from the atmosphere in the industrial production of fertilizers.

D) accelerated removal of carbon from the atmosphere by forests.

E) respiratory production of CO2 by the large human population.

7) The rate of decomposition of leaf litter in woodlands can be strongly influenced by

A) moisture.

B) nitrogen content.

C) leaf toughness.

D) All of the choices are correct.

E) None of the choices are correct.

8) In aquatic ecosystems, leaves with high lignin content decompose

A) rapidly because lignin is a nutrient-rich compound.

B) rapidly because lignin enhances colonization by decomposing fungi.

C) slowly because lignin reduces colonization by decomposing fungi.

D) slowly because lignin is a carbon-poor compound.

E) slowly because lignin-containing leaves sink rapidly.

9) In aquatic ecosystems, the major agents of decomposition are

A) aquatic fungi.

B) bacteria.

C) algae.

D) detritivorous fish.

E) piscivorous fish.

10) Spiraling length of nutrients in streams can be calculated as S = VT. In this equation,

A) V represents nutrient concentration, and T represents water temperature.

B) V represents the speed of water flow, and T represents water temperature.

C) V represents the speed of water flow, and T represents the time required for nutrients to cycle.

D) V represents nutrient retentiveness, and T represents the time required for nutrients to cycle.

E) V represents nutrient retentiveness, and T represents species diversity.

11) Pocket gophers change the nitrogen cycle in prairies because they

A) excavate nitrogen-rich subsoil to the surface.

B) selectively remove nitrogen-fixing legumes from plant communities.

C) bury nitrogen-rich organic material in their burrows.

D) cultivate nitrogen-fixing bacteria in burrow chambers.

E) excavate nitrogen-poor subsoil to the surface.

12) Nitrogen fixation is an energy-demanding process because of the strong ________ bond between the two nitrogen atoms in the N2 molecule.

A) single covalent

B) double covalent

C) triple covalent

D) ionic

E) hydrogen

13) In Judy Meyer and Gene Likens' study of phosphorus in Bear Brook,

A) most phosphorus inputs occurred during spring snowmelt.

B) phosphorus inputs were nearly constant over the year.

C) most phosphorus losses occurred during autumn leaf fall.

D) most phosphorus losses occurred during storms and snowmelt.

E) phosphorus losses were nearly constant over the year.

14) Nitrogen enrichment of ecosystems by human activity is largely driven by

A) addition of nitrogen fertilizers.

B) nitrogen pollution from burning of fossil fuels.

C) nitrogen fixation by bacteria in landfills.

D) both addition of nitrogen fertilizers and nitrogen pollution from burning of fossil fuels.

E) both addition of nitrogen fertilizers and nitrogen fixation by bacteria in landfills.

15) Which of the following are nitrogen fixing organisms?

A) Cyanobacteria

B) Leguminous plants

C) Alders

D) Both cyanobacteria and leguminous plants

E) All of the choices are correct.

16) Clearcutting at Hubbard Brook Experimental Forest sharply

A) increased export of nitrate (NO3-) in stream water.

B) decreased export of nitrate (NO3-) in stream water.

C) increased rates of denitrification in soils.

D) decreased deposition of ammonia (NH3) from the atmosphere.

E) increased deposition of ammonia (NH3) from the atmosphere.

17) The end product of biological nitrogen fixation is

A) N2.

B) NO3-.

C) NO2-.

D) NH3.

E) None of the choices are correct.

18) Fungi and bacteria release nitrogen stored in dead tissue through a decomposition process called

A) nitrogen fixation.

B) ammonification.

C) denitrification.

D) nitrification.

E) nitrogen assimilation.

19) Nitrate is converted to molecular nitrogen, N2, in a process called

A) nitrogen fixation.

B) ammonification.

C) denitrification.

D) nitrification.

E) nitrogen assimilation.

20) The process of denitrification is

A) energy-yielding and aerobic.

B) energy-releasing and aerobic.

C) energy-yielding and anaerobic.

D) energy-releasing and anaerobic.

E) energy-neutral and anaerobic.

21) ________ is the movement of nutrients between pools of an ecosystem and influences the distribution of nutrients.

A) Nutrient shedding

B) Nutrient cruising

C) Nutrient source

D) Nutrient sink

E) Nutrient flux

22) In stream ecosystems, nutrient retentiveness is

A) not related to spiraling length.

B) positively related to spiraling length.

C) inversely related to spiraling length.

D) a logarithmic function of spiraling length.

E) a power function of spiraling length.

23) The major pool of nitrogen in the atmosphere is the direct source of nitrogen for most organisms.

24) The "denitrification" reaction converts nitrate (NO3-) to nitrogen gas (N2) under aerobic conditions.

25) High soil nutrient content usually leads to slower decomposition because soil organisms have less need for nutrients of organic origin.

26) Streams with higher densities of stream invertebrates would be expected to have shorter spiraling lengths.

27) The release of ammonium (NH4+) from decaying organic material is called ________.

28) The release of nutrients from organic material in inorganic form is called ________.

29) ________ is the process of increased nutrient inputs into an ecosystem resulting in increased primary productivity and reduced biodiversity.

30) Nitrogen export was greatest in streams draining watersheds from

A) forested areas.

B) agricultural areas.

C) suburban areas.

D) urban areas.

E) Nitrogen export was similar in streams from forested, agricultural, suburban, and urban areas.

31) Plants in low nutrient ecosystems tend to

A) grow slowly and allocate more resources to shoots than roots.

B) grow rapidly and allocate more resources to shoots than roots.

C) grow rapidly and allocate more resources to roots than shoots.

D) grow slowly and allocate more resources to roots than shoots.

E) grow rapidly and allocate equal resources to roots and shoots.

32) Likens and Bormann found that over 90% of the nutrients in the Hubbard Brook Experimental Forest were in the soil organic matter.

33) Vanni and colleagues found a positive correlation between the N:P ratios of fish and amphibians and their N:P excretion ratios in a tropical stream in Venezuela.

34) How do nutrients and energy move through ecosystems?

A) Nutrients move one direction while energy gets recycled.

B) Nutrients get recycled while energy moves one direction.

C) Nutrients and energy both get recycled.

D) Nutrients and energy both move one direction.

35) Scientists have studied nutrient cycles and determined that these cycles affect the health of the biosphere.  Which cycles are of most concern?

A) Carbon and nitrogen

B) Nitrogen and phosphorus

C) Carbon and phosphorus

D) Carbon, nitrogen, and phosphorus

36) The breakdown of organic matter accompanied by the release of carbon dioxide is called?

A) Mineralization

B) Decomposition

C) Nutrient cycling

D) Disturbance

37) Decomposition rates in forest ecosystems is correlated to which chemical characteristic in the plant litter?

A) Nitrogen concentration

B) Phosphorus concentration

C) Carbon:nitrogen ratio

D) Lignin:nitrogen ratio

38) When comparing temperate and tropical forests, which one has a higher rate of decomposition?  Secondly, what climate factors affect the difference?

A) Temperate; temperature

B) Tropical; moisture

C) Temperate; temperature and moisture

D) Tropical; temperature and moisture

39) When comparing armored catfish, fish, and amphibians which one has the highest phosphorus content and the lowest N:P ratio?

A) Armored catfish

B) Other fish

C) Amphibians

D) They all have the same N:P ratio

40) If Likens and Borman had not applied herbicides to the deforested basin at the Hubbard Brook Experimental Forest nitrate losses would have been reduced.

41) The Baltimore Ecosystem Study LTER found that nitrate levels varied by population density.  Which of the following is correct?

A) Urban areas had higher nitrate outputs.

B) Forested areas had higher nitrate outputs.

C) Forested areas had more nitrogen outputs than suburban areas.

D) Urban areas had lower nitrate outputs than suburban areas.