Biogeochemical Cycles Cailey Henrickson


Heat from the Sun causes water on Earth to evaporate and rise into the sky. This water vapor collects in the sky and forms clouds. When water vapor in the clouds cool down it becomes water again, this is called condensation.

The Water Cycle

Organic Components; Water

Impact of Human Intervention; Reservoirs, Urbanization, Deforestation


When nitrogen is absorbed by the soil, different bacteria help it to change states so it can be absorbed by plants. Animals get their nitrogen from the plants. Fixation is the first step in the process of making nitrogen usable by plants. Bacteria then changes nitrogen into ammonium.

Chemical Reactions; Nitrogen Fixation (Nitrogen + Hydrogen = Ammonia) , Ammonification (decomposition releases ammonium), Nitrification (ammonia and ammonium into nitrites, then nitrates), Denitrification (bacteria into nitrates and nitrogen gas).

The Nitrogen Cycle

Organic/Inorganic Components; Nitrogen

Impact of Human Intervention; Humans take nitrogen out of topsoil through agriculture. Agricultural runoff disrupts aquatic ecosystems by adding excess nitrates to bodies of water.


Carbon is extracted from the atmosphere through photosynthesis. Carbon is combined with other elements in complex ways to form organic molecules important to life. This is later transferred to herbivores. When plants and animals die, most of their carbon is returned to the atmosphere as the organisms decompose.

Chemical Reactions; Photosynthesis (plants use sunlight to make food), Cellular Respiration (cells break down sugars to make energy).

The Carbon Cycle

Organic Components; Carbon

Impact of Human Intervention; Burning Fossil Fuels


Over time, rain and weathering cause rocks to release phosphate ions and other minerals. It is then distributed in soils and water. Plants take up inorganic phosphate from the soil. The plants are then consumed by animals. Once in the plant or animal, the phosphate is incorporated into organic molecules such as DNA. When the plant or animal dies, it decomposes, and the organic phosphate is returned to the soil.

The Phosphorous Cycle

Inorganic Compounds; Carbon Dioxide

Impact of Human Intervention; Raising Livestock, Fertilizers


Created with images by kevinlubin - "Plant" • Launchyourgenius - "Rain drops on my garden!" • dalecruse - "flowers" • Peter23394 - "Animals (212)" • Stirling Council - "Stirling Landscapes"

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