# **The Carbon Cycle**

* Carbon
  * Fundamental element of life.
  * Carbon is found in CO2, which makes up 1% of the atmosphere.
* Plant Matter
  * A portion of atmospheric carbon is removed through photosynthesis in which carbon gets incorporated into plant structures and compounds.
* Terrestrial Biosphere
  * Forests store 90% of the planet's aboveground carbon and 75% of soil carbon.
* Oceans
  * Carbon dissolved in seawater is used for phytoplankton and kelp for photosynthesis.
* Sedimentary Deposits
  * Limestone and carbon trapped in fossil fuels and coal.
* Every year, billions of tons of carbon are exchanged between the atmosphere, plants, soil, and the ocean.

# **Nitrogen Cycle**

* Nitrogen makes up 78% of the atmosphere.
* Essential for amino acids, proteins, and nucleic acids.
* Nitrogen Fixation - Atmospheric nitrogen is converted into ammonia or nitrate ions which are biologically usable forms of nitrogen.
* Nitrification - Ammonia is converted into nitrate and nitrite.
* Assimilation - Plants absorb ammonia, ammonium ions, and nitrate ions through their roots.
* Denitrification - Anaerobic bacteria convert ammonia into nitrites, nitrogen gas, and nitrous oxide.
* Effects of excess nitrogen
  * Ammonia has tripled since the industrial revolution. It decreases air quality.

# **Sulfur Cycle**

* Sulfur in the lithosphere
  * Sulfur in the lithosphere is mobilized by slow weathering of rock material.
* Sulfur in the hydrosphere
  * The main source of sulfur in the oceans is through dissolved sulfate.
* Sulfur in the Soil
  * Main sources come from deposition from the atmosphere, weathering of rocks, release from decay of organic matter and fertilizer, pesticides, and irrigation water.

# **The Water Cycle**

* The water cycle is in a state of dynamic equilibrium by which the rate of evaporation equals the amount of precipitation.
* Processes of the water cycle include evaporation, evapotranspiration, condensation, infiltration, runoff, and precipitation.

# **Role of H2O, C, N, P, and S in the human body**

* Water - Helps to dissolve minerals, makes them accessible to the body, regulates body temperature, and carries nutrients and oxygen to cells throughout the body.
* Carbon - Allows the building of long, complex chains of molecules.
* Nitrogen - Found in many organic molecules, including the amino acids that make up proteins and nucleic acids that make up DNA.
* Phosphorus - Found in the bone and in the molecule ATP.
* Sulfur - Found in 2 amino acids that are important for giving proteins their shape.

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Environmental Science

# **The Carbon Cycle**

* Carbon
  * Fundamental element of life.
  * Carbon is found in CO2, which makes up 1% of the atmosphere.
* Plant Matter
  * A portion of atmospheric carbon is removed through photosynthesis in which carbon gets incorporated into plant structures and compounds.
* Terrestrial

Chapter 5 - Natural Biogeochemical Cycles

Joanna Parlor

View the note Chapter 5 - Natural Biogeochemical Cycles: The Carbon CycleCarbonFundamental element of life.Carbon is found in CO2, which makes up 1% of the atmosphere.Plant MatterA portion of atmospheric carbon is removed through photosynthesis in which carbon gets incorporated into plant structures...