nitrogen/carbon/water cycles

Nitrogen Cycle


  • Living things need organic nitrogen to survive

  • Nitrogen is unusable in the atmosphere (N2)

  • Plants prefer nitrate over nitrite, but will take in both


  1. Nitrogen Fixation

  • N2 is deposited by precipitation, nitrogen fixing bacteria combines the nitrogen with hydrogen

  • Converts N2 into NH3 (ammonia) or NH4 (ammonium)

  • Generally done by bacteria, can also be done using lightning, fossil fuels, industrial processes

  1. Nitrification

  • Most plants cannot use Ammonia

  • Nitrifying bacteria converts Ammonia and Ammonium into NO2 (nitrite) then NO3 (nitrate)

  1. Assimilation

  • Different forms of nitrogen compounds absorbed by plants through soil & roots

    • Nitrate, nitrite, ammonia, ammonium

  •  used to form proteins

  1. Ammonification

  • Nitrogen re-enters soil through plant/animal deaths (decomposition) or waste

  • Produces ammonia

  1. Denitrification

  • Nitrogen goes back into the atmosphere; gets converted into N2 and N2O

  • Occurs where there is a lack of oxygen  

  • Micro organisms need oxygen - “denitrificating bacteria” break down NO3 and use the oxygen

Water Cycle

  1. Evaporation -> condensation -> sublimation 

  2. Liquid to gas -> gas to liquid -> solid to liquid


Evaporation

  • The process where the sun's energy turns water into vapor that rises into the atmosphere

  • Water evaporates (from the ocean, hot surfaces, and from breathing/cellular respiration) into the sky (vapor); as it gets higher, it gets absorbed and turned into clouds

Condensation 

  • Where water vapor cools to form clouds

  • When the clouds contain too much water, they release the water vapor, and it condensates as it reaches the ground.

Precipitation

  • When water falls back to Earth as rain, snow, sleet, or hail 

Collection

  • Where water runs-off and gathers in oceans, lakes, and rivers or infiltrates the ground



Carbon Cycle

Photosynthesis

  • Plants, algae, and some bacteria absorb carbon dioxide (CO2) from the atmosphere.

  • Using energy from sunlight, they convert CO2 and H2O into glucose (a sugar) and oxygen as a waste product.

  • This process incorporated carbon into organic compounds. Moving it from the atmosphere into the biosphere.

Cellular Respiration

  • All living organisms, including plants and animals, perform respiration.

  • They break down the organic molecules (such as glucose) they’ve acquired for energy, a process that requires oxygen and releases carbon dioxide and water as byproducts.

  • This returns carbon to the atmosphere.

Decomposition

  • When plants and animals die, their organic matter is broken down by decomposers (like bacteria and fungi).

  • During this process, the carbon stored in the dead organisms is released back into the atmosphere as CO2.

  • Some carbon can also be incorporated into the soil

ComBUStion

  • This process involves the rapid burning of organic materials.

  • It includes both natural events like wildfires and human activities such as burning fossil fuels (coal, oil, natural gas), which are ancient reservoirs of carbon.

  • Combustion releases large amounts of carbon dioxide into the atmosphere.