Question 1

What is the main avenue by which phosphorus returns to the ocean?

Accepted Answer

A)  dissolved in rainwater 
B)  surface runoff 
C)  wastewater 
D)  dust

Question 2

In the hydrologic cycle, infiltration refers to

Accepted Answer

A)  water evaporating from the environment and condensing into water vapor. 
B)  plants taking up water from the soil. 
C)  the change of water from a liquid to a gas. 
D)  the change of water from a gas to a liquid. 
E)  water from precipitation becoming part of the groundwater.

Question 3

How does ice core sampling help scientists learn what atmospheric carbon dioxide levels were in the past?

Accepted Answer

The answer of How does ice core sampling help scientists...

Question 4

Describe the path of nitrogen as it moves from the atmosphere to the soil, plants, animals, and back to the atmosphere. Describe each process and the location and the form of nitrogen (including chemical formula) at each step.

Accepted Answer

The answer of Describe the path of nitrogen as it...

Question 5

The burning of fossil fuels affects the nitrogen cycle by increasing atmospheric

Accepted Answer

A)  nitrous oxide. 
B)  nitric oxide. 
C)  nitrate. 
D)  ammonia. 
E)  nitrite.

Question 6

How do scientists use watersheds to study nutrient inputs and outputs?

Accepted Answer

The answer of How do scientists use watersheds to study...

Question 7

A summer algal bloom observed in a lake due to excessive agricultural runoff of nutrients would be considered an example of

Accepted Answer

A)  cultural eutrophication. 
B)  nutrient cycling. 
C)  biomagnification. 
D)  nutrient precipitation.

Question 8

Decomposition can be modeled using the following equation: $$m _ { t } = m _ { 0 } \mathrm { e } ^ { - k t }$$ where m_t is the mass of leaf litter that remains at a particular time, m₀ is the initial mass of leaf litter, k is the daily decomposition rate, and t is time in days. Using a decomposition rate (k) of 0.15, how long would it take for 100 g of leaf material to degrade 75 percent?

Accepted Answer

The answer of Decomposition can be modeled using the following...

Question 9

How does phosphorus lead to eutrophication of aquatic ecosystems?

Accepted Answer

The answer of How does phosphorus lead to eutrophication of...

Question 10

In what form does phosphorus move through the environment?

Accepted Answer

A)  Ca(H2PO4)2 
B)  H3PO4 
C)  PO33- 
D)  PO43- 
E)  PH3

Question 11

Where does most decomposition occur in aquatic systems?

Accepted Answer

A)  surface waters 
B)  equally throughout the water levels 
C)  sediments 
D)  stream and river banks

Question 12

The carbon cycle in ecosystems mostly follows the same paths as the movement of

Accepted Answer

A)  water. 
B)  nitrogen. 
C)  phosphorus. 
D)  energy. 
E)  heat.

Question 13

Nitrogen mineralization in the soil is primarily carried out by

Accepted Answer

A)  producers. 
B)  consumers. 
C)  decomposers. 
D)  cyanobacteria. 
E)  nitrogen-fixing plants.

Question 14

The leaf decomposition in a tropical forest

Accepted Answer

A)  increases with increasing leaf solubility. 
B)  decreases with increasing leaf solubility. 
C)  is unaffected by leaf solubility. 
D)  increases with soil pH.

Question 15

In the Hubbard Brook Experimental Forest, researchers found a 90 percent reduction in nitrates leaving the watershed over a 5-year period. To what did they attribute the majority of this reduction?

Accepted Answer

A)  changes in species composition 
B)  recovery from past disturbances 
C)  increased soil pH 
D)  climate change

Question 16

Why is the phosphorus cycle described as less complicated than the nitrogen cycle?

Accepted Answer

The answer of Why is the phosphorus cycle described as...

Question 17

In terms of nutrient loss and nutrient input, how are nutrient levels maintained within a terrestrial ecosystem, thus maintaining a stable level of productivity?

Accepted Answer

The answer of In terms of nutrient loss and nutrient...

Question 18

What did researchers find in the 2012 Canadian study of 21 small watersheds in Quebec?

Accepted Answer

A)  The rate of weathering changed with the size of the watershed. 
B)  The rate of weathering changed with the age of the watershed. 
C)  The rate of weathering changed due to differences in temperature, precipitation, and soil conditions. 
D)  The rate of weathering at all sites was influenced largely by factors associated with climate change.

Question 19

Explain why the Hubbard Brook Experimental Forest was an ideal location for a study dealing with nutrient flow in a watershed.

Accepted Answer

The answer of Explain why the Hubbard Brook Experimental Forest...

Question 20

The large dead zone that forms in the Gulf of Mexico each summer is caused by

Accepted Answer

A)  phytoplankton. 
B)  zooplankton. 
C)  algae. 
D)  archaebacteria.

Exam 21: Movement of Elements in Ecosystems