fv6 - phosphorus cycle

AP Environmental Science: The Phosphorus Cycle

Page 1: Overview of the Phosphorus Cycle

  • Importance of Phosphorus

    • Essential for DNA, RNA, and ATP.

    • Acts as a limiting macronutrient.

  • Cycle Characteristics

    • Limited interactions with the atmosphere; primarily cycles between land and water.

    • Exists mainly in one chemical form: PO4 (phosphate).

  • Release and Transport

    • Weathering of rocks releases phosphorus into the environment.

    • Transported through rain and runoff to soil and water bodies.

  • Absorption by Organisms

    • Living organisms absorb phosphorus for DNA and other biomolecule production.

    • Upon death, organisms release phosphorus back into the environment, restarting the cycle.

  • Storage of Excess Phosphorus

    • Excess phosphorus can remain stored in rocks or soil at the bottom of water bodies.

Page 2: Human Impacts on the Phosphorus Cycle

  • Anthropogenic Sources

    • Major sources include laundry detergents and synthetic fertilizers.

  • Role in Plant Growth

    • Phosphorus is crucial for plant growth; often added to fertilizers.

  • Consequences of Runoff

    • Phosphorus runoff can accumulate in groundwater, disrupting ecosystem balance.

    • Leads to eutrophication, where nutrient overload degrades water quality and creates dead zones.

Page 3: Key Concepts and Definitions

  • Aquatic Functions

    • Roles of aquatic ecosystems: water purification, nutrient cycling, habitat provision, flood control, climate regulation.

  • Biomolecules

    • Organic molecules essential for life: carbohydrates, lipids, proteins, nucleic acids.

  • Decomposition

    • Breakdown of organic matter by decomposers, releasing nutrients back into the environment.

  • DNA

    • Genetic material essential for growth, development, and reproduction of organisms.

  • Geologic Uplift

    • Process raising Earth's crust, forming mountains and plateaus.

  • Groundwater

    • Water beneath the surface in aquifers, vital for drinking and ecosystems.

  • Human Impacts

    • Activities disrupting natural phosphorus flow: excessive fertilizer use, deforestation, pollution.

  • Limiting Nutrient

    • Essential nutrient in short supply, restricting organism growth.

  • Organic Phosphorus

    • Phosphorus in living organisms, crucial for biological processes.

  • Phosphate Rocks

    • Sedimentary rocks rich in phosphate minerals, used for fertilizers.

  • Phosphorus Cycle

    • Movement of phosphorus through rocks, water, soil, and organisms.

  • Runoff

    • Water movement over land into bodies of water, often carrying nutrients.

  • Sedimentation

    • Accumulation of particles settling out of fluid due to gravity.

  • Synthetic Fertilizers

    • Man-made nutrients for plant growth, commonly used in agriculture.

  • Weathering

    • Breakdown of rocks and minerals, contributing to soil formation and nutrient cycling.

Page 4: Summary of Processes

  • Weathering

    • Crucial for shaping landscapes and nutrient cycling, particularly phosphorus.

  • Overall Cycle Dynamics

    • The phosphorus cycle is essential for ecosystem health, influenced by both natural processes and human activities.