Ecology Biogeochemical Cycles 2

Question 1

Which process converts atmospheric nitrogen (N₂) into ammonia (NH₃) that plants can use?

Accepted Answer

Nitrogen fixation

Answer

Nitrification

Answer

Denitrification

Answer

Ammonification

Question 2

In the phosphorus cycle, what is the primary reservoir of phosphorus on Earth?

Accepted Answer

Rocks and sediments

Answer

The atmosphere

Answer

Ocean water

Answer

Living organisms

Question 3

What process do decomposers perform that is essential to the nitrogen cycle?

Accepted Answer

Ammonification

Answer

Nitrification

Answer

Denitrification

Answer

Nitrogen fixation

Question 4

Which human activity has most dramatically increased the rate of nitrogen entering ecosystems?

Accepted Answer

Synthetic fertilizer production via the Haber-Bosch process

Answer

Burning fossil fuels

Answer

Deforestation

Answer

Irrigation

Question 5

During the sulfur cycle, which process releases sulfur dioxide (SO₂) into the atmosphere?

Accepted Answer

Volcanic eruptions and fossil fuel combustion

Answer

Photosynthesis

Answer

Decomposition of plant cellulose

Answer

Nitrogen fixation

Question 6

What role do mycorrhizal fungi play in the phosphorus cycle?

Accepted Answer

They extend plant root surface area to absorb more phosphate from soil

Answer

They fix atmospheric phosphorus

Answer

They convert phosphate into phosphine gas

Answer

They store phosphorus in their fruiting bodies for later use

Question 7

In a wetland ecosystem, which microbial process removes bioavailable nitrogen by converting nitrate back to N₂ gas?

Accepted Answer

Denitrification

Answer

Nitrification

Answer

Assimilation

Answer

Ammonification