APES Cycles (Topics 1.4-1.7)

Flashcards covering key vocabulary and concepts from lectures on the Carbon Cycle, Nitrogen Cycle, Phosphorus Cycle, and Hydrologic Cycle.

Carbon Cycle

The movement of carbon (CO2, CH4, etc.) between sources and sinks. Some steps are fast, others are slow.

Sink

A reservoir that stores more of a molecule than it releases.

Source

A reservoir that releases more of a molecule than it stores.

Combustion

Converts fossil fuels and plants into CO2.

Nitrogen Cycle

The movement of Nitrogen (N) between sources and sinks. Steps are relatively fast compared to the Carbon cycle and reservoirs don't hold N for long.

Nitrogen Fixation

Turning nitrogen from unusable forms to usable forms (NH3 or NO3).

Bacterial Fixation

Bacteria in the soil or in symbiosis with plant roots convert N2 into ammonia (NH3).

Synthetic Fixation

Humans combust FF's turning N2 into nitrate (NO3).

Assimilation

Plants/Animals taking in N and incorporating it into their body.

Ammonification

Soil bacteria, microbes, and decomposers convert waste and dead biomass back into NH3 and return it to the soil.

Nitrification

Conversion of NH3 into nitrite (NO2) then nitrate (NO3) by bacteria.

Denitrification

Conversion of soil N (NO3) into nitrous oxide (N2O) gas, which returns to the atmosphere.

Phosphorus Cycle

Movement of phosphorus between sources and sinks. Cycle is very slow compared to C and N cycles.

Weathering

Major natural source of phosphorus, wind and rain break P down and release it into nearby soil/water.

Eutrophication

Excess nitrogen and phosphorus that can lead to algae blooms.

Sedimentation

The process by which N particles don’t dissolve and fall to the bottom of the ocean, leading to the accumulation of sediment rock in bodies of water or soil.

Geologic Uplift

The process by which tectonic plates collide, forcing up rock layers that for mountains, which can restart P cycle.

Hydrologic Cycle

Movement of H2O between sources/sinks in different states.

Transpiration

Plants draw up groundwater from roots to leaves, then water evaporates from stomata in leaves.

Condensation

Water vapor turns into liquid water.

Evapotranspiration

The combined process of evaporation from land and water surfaces and transpiration from plants through leaf stomata to the atmosphere.