AP Enviro: Nitrogen Cycle

Nitrogen

A building block of proteins and nucleic acids, essential for plant growth.

Limiting Nutrients

Nutrients that, when depleted, halt plant growth.

Nitrogen Cycle

The movement of nitrogen through the biosphere among various sources and sinks.

Atmosphere

The largest sink of nitrogen, comprising 78% nitrogen gas, which is biologically unusable.

Nitrogen Fixation

The process of converting nitrogen gas into usable forms for plants and algae.

Nitrogen Fixing Bacteria

Bacteria found in the root nodules of legumes that facilitate nitrogen fixation.

Nitrification

The process of converting nitrite into nitrate, making nitrogen usable for plants.

Ammonia

The initial form of nitrogen after fixation, which can be converted into nitrite.

Nitrite

A more usable form of nitrogen that is converted into nitrate during nitrification.

Nitrate

The final usable form of nitrogen for plants after nitrification.

Assimilation

The process by which nitrogen is incorporated into animal tissues when herbivores consume plants.

Ammonification

The breakdown of organic matter by fungi and bacteria to convert it back into ammonium.

Mineralization

Another term for ammonification, where organic nitrogen is converted to ammonium.

Denitrification

The process of returning nitrogen gas to the atmosphere under anaerobic conditions by bacteria.

Leaching

The process of nitrogen dissolving in water and moving into soil and water sources.

Runoff

The movement of nitrogen from farms into bodies of water, contributing to excess plant growth.

Eutrophication

The overgrowth of plants in water bodies due to excess nitrogen from runoff and leaching.

Fertilizer

Human usage of fertilizers that leads to nitrogen runoff into waterways.

Nitrogen Oxides (NOx)

Compounds released from burning fossil fuels that contribute to acid rain.