Chapter 19 - Nutrient Cycling

What forms of nitrogen are usable form for plants and animals?

Ammonia & Nitrates

Nitrogen cycle

• nitrogen fixation

• ammoniafication

• nitrification

• assimilation

• dentrification

Nitrogen fixation

Ammoniafication

decomposers transform nitrogen-containing parts of organic matter into ammonia (NH3) or ammonium (NH4)

Nitrification

bacteria transform ammonia (NH₃) into nitrates which plants absorb

Assimilation

process by which plats absorb ammonia (NH3) and nitrates through their roots to make proteins.

Denitrification

some bacteria convert nitrates (NO₃) in the soil to N₂ gas which is released into the atmosphere.

Fertilizers 

contain nitrates. if excess nitrates get into water environments, it can kill algae which decreases the amount of oxygen there. 

Human influence on the nitrogen cycle

• fertilizers

• fossil fuels