1.6 - Phosphorus Cycle Flashcards
What is the phosphorus cycle?
The movement of Phosphorus particles through sources and sinks/reservoirs
What are phosphorus’ major reserves
Rocks and sediment
Why is phosphorus the slowest cycle?
- Phosphorus is formed as phosphate so it takes a long time for Phosphorus minerals to be weathered out of rocks & carried into soil/bodies of water
- No gas phase of Phosphorus (doesn’t enter atmosphere)
- Because it cycles so slowly, it is a limiting nutrient, meaning plant growth in ecosystems is often limited by Phosphorus availability in soil/water - meaning phosphorus has to be given as nutrients in a limited manner then decomposed in that limited quantity (very slow)
Why is phosphorus important?
Phosphorus is needed by all organisms for DNA, ATP (energy), bone & tooth enamel in some animals
What is a major natural source of phosphorus
Weathering of rocks
Explain the phosphorus cycle through the weathering of rocks
- Wind & rain break down rock & phosphate (PO4-3)
- released and dissolved into water
- rain water carries phosphate into nearby soils & bodies of water
What happens because the phosphorus cycle is so slow?
Weathering is so slow that P is often a limiting nutrient in aquatic & terrestrial ecosystems
What are synthetic sources of phosphorus
mining phosphate minerals & adding to products like synthetic fertilizers & detergents/cleaners
Explain what happens with synthetic sources of phosphorus
- Synthetic fertilizers containing phosphates are added to lawns or ag. Fields; runoff carries P into nearby bodies of water
- Phosphates from detergents & cleaners enter bodies of water via wastewater from homes
Assimilation in phosphorus cycle
- Just like N, P is absorbed by plant roots & assimilate into tissues
- animals assimilate P by eating plants or other animals
Decomposition in phosphorus cycle
Animal waste, plant matter & other biomass is broken down by bacteria/soil decomposers that return phosphate to soil
How does Decomposition and Assimilation relate
They create a loop within the phosphorus cycle
Explain sedimentation in the phosphorus cycle
- Phosphate doesn’t dissolve very well into water; much of it forms solid bits of phosphate that fall to the bottom as sediment (sedimentation)
- P sediments can be compressed into sed. rock over long time periods by pressure of overlying water
What is geological uplift
- tectonic plate collision forcing up rock layers that form mountains
- allows for the phosphorus cycle to start again with wethering and release of phosphate from rocks
What causes eutrophication
extra input of Nitrogen and phosphorus into aquatic ecosystems
What is fueled by extra nitrogen and phsophorus
algae blooms
Explain the process of eutrophication
- Algae bloom covers surface of water, blocking sunlight & killing plants below surface
- Algae eventually die-off; bacteria that break down dead algae use up O2 in the water (b/c decomp. = aerobic process)
- Lower O2 levels (dissolved oxygen) in water kills aquatic animals, especially fish
- Bacteria use up even more O2 to decompose dead aq. animals
- Creates pos. feedback loop: less O2 → more dead org. → more bacterial decomposition → less O2
What can eutrophication occur from
Can occur from fertilizer runoff, human/animal waste contamination
Simple Photos explanation of eutrophication
- nutrient load up - excessive nutrients from fertilizers are flushed from land into rivers or lakes by rainwater
- plants flourish - these pollutants cause aquatic plant growth
- algae blooms, oxygen is depleted - algae blooms preventing sunlight reaching other plants. The plants die and oxygen in the water is depleted
- Decomposition further depletes oxygen - dead plants are broken down by bacteria decomposers, using even more oxygen in the water
- death of the ecosystem - oxygen levels reach a point where no life is possible. Fish and other organisms die
