Biogeochemical Cycles Summary

Biogeochemical Cycles Overview

  • Nutrient cycling, also known as biogeochemical cycles, is the movement of matter between organisms in the biosphere.

  • Nutrients are finite and must be recycled.

  • Key cycles include: carbon-oxygen, water, nitrogen, sulfur, and phosphorus.

Carbon-Oxygen Cycle

  • Carbon is essential for life, derived from solar energy captured by plants.

  • Processes:

    • Photosynthesis: Plants convert CO2 to O2.

    • Respiration: Organisms consume O2 and release CO2.

  • Human Impacts:

    • Greenhouse gases from resource overconsumption increase atmospheric CO2.

    • Global warming leads to ice cap melting, climate change.

    • Deforestation reduces oxygen production and harms biodiversity.

Water Cycle (Hydrologic Cycle)

  • Regulates Earth's water flow and temperature.

  • **Processes:

    • Evaporation:

    • Major water transfer from Earth's surface to the atmosphere.

    • Transpiration:

    • Water vapor through plant stomata.

    • Condensation:

    • Vapor to liquid state.

    • Precipitation:

    • Water returns to Earth through rain/snow.

    • Runoff:

    • Transfers water into lakes/rivers, can degrade water quality by carrying excess nutrients.

    • Groundwater:

    • Absorbed water used for drinking and irrigation.

  • Human Impacts:

    • Water usage for agriculture, urbanization; overuse of aquifers leads to scarcity and diseases.

Nitrogen Cycle

  • Comprises 78% of air; vital for DNA, RNA, and proteins.

  • Processes:

    • Nitrogen fixation by bacteria and lightning makes nitrogen usable.

  • Human Impacts:

    • Excess nitrogen from fertilizers and waste leads to health issues and eutrophication.

Sulfur Cycle

  • Important for amino acids and protein formation.

  • Processes:

    • Sulfur is released through decomposition, volcanic activity, and fossil fuel burning.

  • Human Impacts:

    • Increased atmospheric sulfur, leading to acid rain, harmful to ecosystems and infrastructure.

Phosphorus Cycle

  • Essential for bones, teeth, DNA, and ATP.

  • Processes:

    • Present in rocks as calcium phosphate; released during rock breakdown.

  • Human Impacts:

    • Mining for phosphate and runoff from agriculture leads to water quality issues and ecosystem imbalances.