1.5 Nitrogen Cycle DB

Which is the largest reservoir of Nitrogen?

• Atmosphere

• Soil

• Plants

True or False:  N2 gas is useful for plants and animals

• True

• False

Rhizobacteria living in root nodules of a legume is an example of which symbiotic relationship?

• Parasitic

• Commensalistic

• Mutualistic

Human interaction with the nitrogen cycle is primarily due to 

• the leaching of nitrates into terrestrial ecosystems

• the breakdown of ammonium into ammonia for industrial uses

• the acceleration of the nitrification process in aquatic ecosystems

• the decreased assimilation of ammonium and nitrates

Which of the following does NOT fix nitrogen from the atmosphere into a biologically available form?

• Soil-dwelling bacteria

• Rhizobacteria in the root nodules of legumes

• Humans creating ammonia with the use of fossil fuels for energy

• Specialized lichen and moss species

Which of the following is an INCORRECT pairing of human activity and a nitrogen cycle consequence?

• Excess fertilizer use --> nitrate runoff into bodies of water

• Excess fertilizer use --> increased denitrification and N2O entering the atmosphere

• Synthetic fertilizer production --> less Nitrogen available for plants in natural ecosystems

Which two nitrogen cycle steps form a "mini-loop" cycling nitrogen back and forth between living organisms and the soil?

• Assimilation & fixation

• Assimilation & ammonification

• Ammonification & denitrification

• Assimilation & nitrification

Which of the following is NOT TRUE of Denitrification

• it returns nitrogen to the atmosphere

• it is carried out by soil bacteria 

• It leads to an increase in biologically available nitrogen for plants

• It can occur in waterlogged agricultural soils with excess nitrate