Biogeochemical Cycles By: Anna-Austin Boyers

the water cycle

Description: A continuous cycle of moving water in, across, and on the Earth. The water cycle causes water to change into different states throughout: from liquid to vapor to ice, and then all over again. The main stages are evaporation (when water turns into vapor and rises into the clouds), sublimation (snow and ice changing into water vapor), evapotranspiration (water is lost from the ground surface), condensation (water vapor throughout the air changes to liquid water), precipitation(precipitation released from the clouds in the form of rain, snow, sleet, etc.) , water storage (water that is being stored for long periods of time in the form of glaciers and ice caps), surface runoff (precipitation that is runoff or flows across the land), streamflow (amount of water flowing into the river), freshwater storage (freshwater that is being stored), and groundwater storage (water that is being stored below Earth's surface).

Chemical Reactions: There are no chemical reactions in the water cycle, however when the temperature rises it helps evaporation occur more swiftly.

Organic and Inorganic Compounds: Organic- Carbon (in sedimentary rock), Vegetation roots (in water when the plants die), Microorganisms (transfer from soil to water from organic matter). Inorganic- Chloride (makes the water taste salty), Sulfate (causes it to be hard), Iron (humans need in their diet), Fluoride (needed for our teeth and bones but can be toxic in high amounts).

Movement: The water is evaporated from bodies of water, the ground, etc. and moves upward. Then it goes through the process of condensation, and moves through the rest of the cycle after that point.

Ways Humans Intervene With The Water Cycle: Withdrawing water for irrigation uses, discharging water into the runoff streams, like trash, fertilizers, chemical products, etc. The contaminated water can affect plant and animal life.

The Carbon cycle

Description: The carbon cycle is the process in which carbon travels from the atmosphere to the plants, and then from plants to animals, and then back into the ground and into the atmosphere. It also may be available in the form of fossil fuels after the plants and animals die.

Chemical Reactions: Carbon dioxide goes throughout the cycle as a gas, and is moved as plants and animals die and decay, and each time an organism exhales. It is also chemically formed into fossil fuels and released as a greenhouse gas.

Organic and Inorganic Compounds: Organic- Sugars, proteins and fats. Inorganic- carbon dioxide and methane.

Movement: The carbon moves from the ground, to the plants, and then the animals, and then back into the ground again.

Human Intervention: The burning of fossil fuels and deforestation are the two main human impacts on the carbon cycle.

the nitrogen cycle

Description: The process of chemical reactions in which nitrogen that is found in the atmosphere is found in soil and water compounds, transferred to plants and animals, released by decomposition to the soil and water again, and then transferred back into the atmosphere by denitrification.

Chemical Reactions: Nitrogen Fixation- where N2 is converted to ammonium, Denitrification- anaerobic process that is carried out by denitrifying bacteria, which converts nitrate to dinitrogen, Nitrification- ammonium that is produced by decomposition and is then converted to nitrate, Nitrogen Mineralization- organic matter converted back intro inorganic nitrogen, Nitrogen Uptake- ammonium is taken up by plant, bacteria, or another organim

Organic and Inorganic Compounds: Organic nitrogen is found in any living organisms, and inorganic nitrogen is found in ammonium.

Movement: Circulates from the atmosphere, to the soil, to the plants and animals, back to the soil, and finally back into the atmosphere.

Human Intervention: Humans affect the nitrogen cycle by deforestation, burning fossil fuels, factories emitting pollutants, etc.


Description: The process of phosphorous circulating throughout the atmosphere by moving through rocks, water, soil sediments, and organisms. Phosphates are a critical part of life because they are part of the structural framework for DNA and RNA, and a critical component of ATP. Phosphorus is constantly circulating through water, the crust, and through living organisms. Phosphates that are released and dissolve into the soil water, and then are taken up by plant roots. Animals are part of the equation when they eat the plants/herbivores, and then dead organisms and wastes return phosphorus back to the soil, streams, etc.

Chemical Reactions: As phosphorus is circulated throughout this cycle, phosphates react with halogens to form phosphorus trihalides. Phosphorous exists in two major forms, white phosphorous and red phosphorous. When white phosphorous is exposed to damp air, it reacts by glowing in the dark. These are all chemical reactions that are involved in the phosphorous cycle.

Organic and Inorganic Compounds: The organic compounds in this cycle are the molecules such as DNA, and the phosphorous that is eventually broken down into inorganic material. The inorganic compounds in this cycle are the amounts of phosphorous that are constantly circulating throughout the atmosphere.

Movement: The movement of the phosphorus cycle goes from the atmosphere, to the soil, then to the plants, and then the animals, and finally back into the atmosphere again when they die or decay.

Human Intervention: Humans mainly intervene with the phosphorus cycle by using commercial fertilizers and by raising lots of livestock, such as hogs. These affect the phosphorus cycle because they are both very high in phosphorus, and causes excess amounts to go into the atmosphere.


Created with images by MartinStr - "air bubbles diving underwater"

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