Biogeochemical Cycles

The exchange of matter through the biosphere is referred to as the biogeochemical cycle. This involves living organisms, geological processes, and chemical processes, which you can tell from its name!

A classic example of this would be weathering, where rock particles become part of the soil. These cycles are very important for the ecosystem's balance.

Four important cycles that I'll explain are the water cycle, the carbon & oxygen cycle, the nitrogen cycle, & the phosphorus cycle. These cycles are necessary for the Earth!

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Water Cycle

Water constantly evaporates into the atmosphere from bodies of water, organisms, and soil. It then becomes water vapor.

Clouds eventually form when cooling water vapor condenses. Then, water falls from those clouds as precipitation.

The three stages of the water cycle are evaporation, condensation, and precipitation. Organisms would not be able to survive without the water cycle.

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Carbon & Oxygen Cycle

During photosynthesis, green plants & algae convert carbon dioxide & water into carbs, releasing oxygen back into the air.

Carbon dioxide is recycled when auto/heterotrophs release it back into the air during cellular respiration.

When organic matter is buried underground & converted, it will eventually be released from fossil fuels when burned, going back into the atmosphere.

Carbon & oxygen can also become rocks, only being re-released into the atmosphere when exposed to weathering & erosion.

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Nitrogen Cycle

Animals and plants can't use nitrogen directly from the atmosphere. Nitrogen gas is captured from the air by bacterial species. The process of capture & conversion of nitrogen into a plant-usable form is nitrogen fixation.

Nitrogen is returned to the soil when an animal urinates. It is then used by plants. When organisms die, nitrogen is converted to ammonia and then back to nitrogen.

In a process called denitrification, nitrogen is returned to the atmosphere when soil bacteria convert nitrogen compounds to nitrogen gas.

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Phosphorus Cycle

Phosphorus is an element that is essential for the growth & development of organisms. There are two cycles of phosphorus.

Short-Term

Phosphorus is cycled from the soil to producers and then to consumers. When organisms die/waste, decomposers return it to the soil.

Long-Term

Weathering/erosion of rocks eventually adds phosphorus to the cycle.