Deck 19: Nutrient Cycling and Retention

Question 1

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.

Answer 1

B

Question 2

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.

Answer 2

D

Question 3

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.

Answer 3

C

Question 4

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

Question 5

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.

Question 6

In aquatic ecosystems,the major agents of decomposition are

A) aquatic fungi.
B) bacteria.
C) algae.
D) detritivorous fish.
E) piscivorous fish.

Question 7

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

Question 8

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.

Question 9

Which of the following are nitrogen fixing organisms?

A) cyanobacteria
B) leguminous plants
C) alders
D) All of the choices are correct.
E) both cyanobacteria and leguminous plants

Question 10

Which of the following is NOT an assumption of the t-test?

A) Each sample is drawn from a population with a normal distribution.
B) The two populations being compared have equal variances.
C) The two populations being compared have equal means.
D) All of each sample is drawn from a population with a normal distribution, the two populations being compared have equal variances, and the two populations being compared have equal means are assumptions.
E) None of each sample is drawn from a population with a normal distribution, the two populations being compared have equal variances, and the two populations being compared have equal means are assumptions.

Question 11

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.

Question 12

The end product of biological nitrogen fixation is

A) N₂.
B) NO₃^-.
C) NO₂^-.
D) NH₃.
E) None of the choices are correct.

Question 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.

Question 14

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

A) nitrogen fixation.
B) ammonification.
C) denitrification.
D) nitrification.
E) nitrogen assimilation.

Question 15

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.

Question 16

Phosphorus is an important constituent of

A) DNA.
B) bone tissue.
C) RNA.
D) ATP.
E) All of the choices are correct.

Question 17

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.

Question 18

"Nitrogen fixation" refers to the conversion of
Rev: 12_06_2013_QC_42091

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^-).

Question 19

"Nitrification" is the conversion of
Rev: 12_06_2013_QC_42091

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^-).

Question 20

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.

Question 21

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

Question 22

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

Question 23

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.

Question 24

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.

Question 25

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

Question 26

_____________ 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

Question 27

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

Question 28

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

Question 29

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

Question 30

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.

Question 31

The release of nutrients from organic material in inorganic form is called _____________.

Question 32

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.

Question 33

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.

Question 34

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

Question 35

A normal distribution is assumed for which of the following statistical tests?

A) Student's t-test
B) 95% confidence intervals
C) regression analysis
D) All of the choices are correct.
E) both Student's t-test and 95% confidence intervals

Question 36

In a normal distribution,_____ of the observations fall within one standard deviation of the mean.

A) 31.7%
B) 68.3%
C) 95.5%
D) 98.3%
E) 99.7%