Unit 1 APES Review - Phos/Water/Nitrogen Cycle

phosphorus

needed by plants and animals - no atmosphere

Phos. Cycle

limiting factor in most ecosystems - mainly in aquatic ecosystems

Water cycle

mainly ocean water - earth is 71% water

movement

moves through solid (ice) to liquid to gas

Nitrogen

needed by all organisms

Fixation

removing nitrogen from the air an converting it to ammonia

Ammonification

• dead organisms and waste decompose, ammonia and ammonia ions are released into environment

• bacteria and fungi

nitrification

converting ammonia in the soil to the nitrate ion

denitrification

converting nitrates back to nitrogen gas

Nitrogen’s largest reservoir

atmosphere - 78% of air

what contains nitrogen

• DNA - RNA - Protein Molecules

Water cycle stages

• precipitation

• evaporation

• concentration

• Infiltrate soil

• percolate (sink into ground)