FREE Ecology Biogeochemical Cycles Questions and Answers

Question 1

In the nitrogen cycle, which process is responsible for converting atmospheric nitrogen (N2), a form unusable by most plants, into ammonia (NH3), making it available to the ecosystem?

Accepted Answer

Nitrogen Fixation

Answer

Denitrification

Answer

Nitrification

Answer

Ammonification

Question 2

A significant increase in agricultural fertilizer runoff into a local lake leads to an algal bloom, followed by a sharp decline in dissolved oxygen and a subsequent fish kill. This entire process is known as:

Accepted Answer

Eutrophication

Answer

Ocean acidification

Answer

Biomagnification

Answer

Denitrification

Question 3

Unlike the carbon and nitrogen cycles, the phosphorus cycle lacks a significant atmospheric component. What is the primary reservoir for phosphorus?

Accepted Answer

Sedimentary rock

Answer

Living organisms

Answer

Ocean water

Answer

The atmosphere

Question 4

Which of the following human activities is the most significant driver of the recent, rapid increase of carbon dioxide in the atmospheric reservoir of the carbon cycle?

Accepted Answer

Combustion of fossil fuels

Answer

Increased rates of cellular respiration

Answer

Deforestation and land-use change

Answer

Volcanic eruptions

Question 5

In an agricultural field with waterlogged, anaerobic soil, a farmer notices that despite applying nitrate-based fertilizer, the nitrogen availability for crops is decreasing. Which microbial process is most likely responsible for this loss of usable nitrogen?

Accepted Answer

Denitrification

Answer

Nitrification

Answer

Ammonification

Answer

Nitrogen Fixation

Question 6

What is the primary way that water moves from the biosphere (specifically, from plants) to the atmosphere in the hydrologic cycle?

Accepted Answer

Transpiration

Answer

Precipitation

Answer

Condensation

Answer

Percolation