Ecology Biogeochemical Nutrient Cycles Questions and Answers

Question 1

The conversion of atmospheric nitrogen gas (N2) into ammonia (NH3) or ammonium (NH4+), forms usable by plants, is performed primarily by certain bacteria. What is this critical process called?

Accepted Answer

Nitrogen Fixation

Answer

Denitrification

Answer

Nitrification

Answer

Ammonification

Question 2

A large-scale deforestation project removes a significant portion of a tropical rainforest. Which of the following describes the most immediate and significant impact on the global carbon cycle?

Accepted Answer

A decrease in the rate of carbon sequestration from the atmosphere.

Answer

An increase in the amount of carbon stored in sedimentary rock.

Answer

A decrease in atmospheric carbon dioxide due to increased soil absorption.

Answer

An increase in the rate of oceanic carbon uptake.

Question 3

Which of the following characteristics most significantly distinguishes the phosphorus cycle from the carbon and nitrogen cycles?

Accepted Answer

It lacks a significant gaseous or atmospheric phase.

Answer

It is primarily driven by the metabolic activities of microorganisms.

Answer

It is significantly and directly impacted by the combustion of fossil fuels.

Answer

It is the fastest of the major biogeochemical cycles.

Question 4

An ecologist observes a massive algal bloom in a freshwater lake following a period of heavy rainfall that caused significant runoff from a nearby agricultural area. The overgrowth of algae is most likely caused by an excess of which two limiting nutrients commonly found in fertilizers?

Accepted Answer

Nitrogen and Phosphorus

Answer

Carbon and Sulfur

Answer

Potassium and Calcium

Answer

Iron and Magnesium

Question 5

In the context of the hydrologic cycle, what is the term for the process by which water vapor is released from plants into the atmosphere?

Accepted Answer

Transpiration

Answer

Infiltration

Answer

Condensation

Answer

Precipitation

Question 6

Denitrification is a critical step in the nitrogen cycle that returns nitrogen gas to the atmosphere. Which of the following best describes this process?

Accepted Answer

Nitrate (NO3-) is converted to nitrogen gas (N2) by anaerobic bacteria.

Answer

Ammonium (NH4+) is converted to nitrate (NO3-) by aerobic bacteria.

Answer

Organic nitrogen is converted to ammonium (NH4+) by decomposers.

Answer

Nitrogen gas (N2) is converted to ammonia (NH3) by bacteria in root nodules.

The conversion of atmospheric nitrogen gas (N2) into ammonia (NH3) or ammonium (NH4+), forms usable by plants, is performed primarily by certain bacteria.What is this critical process called?

The conversion of atmospheric nitrogen gas (N2) into ammonia (NH3) or ammonium (NH4+), forms usable by plants, is performed primarily by certain bacteria.
What is this critical process called?