APES 1.6 Phosphorous Cycle

Phosphorous Cycle

• No atmospheric component
• Limiting factor like nitrogen

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Breakdown of cycle:

• Weathering of rock contributes phosphorous to the land, some into the ocean
• In fertilizer, so gets into streams, the earth, or absorbed by plants
• Excretion by animals and decomposition also returns phosphates to land/sea
• Dissolved phosphates precipitate out of solution and contribute to ocean amounts
• Organisms need phosphorous for many functions: In DNA, RNA, ATP, etc.
• Huge liming reagent
• Not very soluble in water, so much of it precipitates out as phosphate (PO4-3)

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• In phosphorous-limited environments, algal blooms occur and create very oxygen-poor bodies of water, killing biodiversity. They cause dead zones in water.

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