Biogeochemical cycles

Photosynthesis

Photosynthesis

CO2 from atmo. to plants

Burial

Carbon in plants or ocean becomes oil, coal, or methane

Exchange

CO2 from atmo. dissolves in ocean water

Respiration / decomposition (carbon)

CO2 released from living organisms as they process food

Combustion (carbon)

Fossil fuels are burned releasing CO2

Abiotic fixation

Atmo. N2 → NO3 (nitrate) from lightning or fertilizer production

Biotic fixation

Atmo. N2 → NH4 from bacteria in legumes (ex. clover, beans)

Ammonification / decomposition (nitrogen)

Dead matter → NH4 from decomposers

Nitrification

NH4 (ammo.)→ NO3 (nitrate) and NO2 from soil bacteria

Assimilation

NH4 (ammo.), NO3 (nitrate), NO2 (nitrite) in soil absorbed into plants

Denitrification

NO3 (nitrate) and NO2 (nitrite)→ atmo. N2 from soil bacteria

Leaching (nitrogen)

NH4 (ammo.), NO3 (nitrate), NO2 (nitrite) removed from sol by water

Precipitation

Water falls as snow or rain

Runoff

Water moves across soil towards a body of water

Infiltration

Water moves through the ground into an aquifer

Condensation

Water vapor loses heat and becomes liquid

Transpiration

Water evaporates from plant leaves

Evaporation

Liquid water becomes water vapor in the atmo.

Weathering

Rock is broken down by wind and water, releasing PO4 (phosphorus)

Decomposition (phosphorus)

PO4 (phosphorus) released from dead/decaying organic matter

Leaching (phosphorus)

PO4 (phosphorus) is carried away when water infiltrates through soil

Combustion (sulfur)

SO4 (sulfate) released in volcanic eruptions, burning fossil fuels or wood

Acid percipitation

Sulfuric acid in atmo. mixes with rain or snow