Lecture Notes: Understanding Earth’s Cycles - Hydrologic and Carbon Cycles

Introduction: Cycles in Nature

• The Earth operates on cycles.
• All matter and energy have been recycled since the Big Bang.
• Earth is a closed system with biogeochemical cycles for matter distribution.

Hydrologic Cycle

• Key Processes and Definitions:

  • Precipitation: Forms include rain, hail, snow, sleet, graupel; occurs when atmospheric water condenses.
  • Evaporation: Liquid to gas transformation.
  • Sublimation: Solid to gas transition.
  • Condensation: Gas to liquid; forms clouds.
  • Deposition: Gas to solid conversion.

• Water Reservoirs:

  • Oceans, atmosphere, ice caps, and land water storage (lakes, ponds, wetlands).
  • Oceans are the ultimate destination for most water on Earth.

• Water Movement:

  • Clouds form and move water across the globe.
  • Runoff: Movement of water from land to ocean.
  • Evapotranspiration: Water movement from plants to the atmosphere.
  • Solar energy drives evaporation and the hydrologic cycle.

Carbon Cycle

• Importance:

  • Carbon is critical for living organisms and regulates Earth's temperature.
  • Carbon's presence in rocks, oceans, and atmosphere.

• Carbon in Living Things:

  • Plants absorb CO2 for photosynthesis, releasing it via respiration.
  • Carbon becomes part of plant mass (e.g., trees).

• Carbon Reservoirs and Movement:

  • Oceans absorb CO2; phytoplankton use it for photosynthesis.
  • Formation of limestone from phytoplankton shells.
  • Release of CO2 from burning fossil fuels.
  • Permafrost stores carbon; melting releases CO2 and methane.

• Impact on Climate:

  • Rising atmospheric CO2 contributes to global warming.
  • Feedback loops from melting permafrost exacerbate climate change.

Conclusion

• Understanding cycles is crucial for grasping ecological and climate dynamics.
• The lecture emphasizes the need to study ecology to address climate challenges.

• Credits: Written by Jesslyn Shields and Blake de Pastino.
• Production Team: Technical Director & Editor - Nick Jenkins; Graphics by Amber Bushnell and Peter Winkler; Sound Design by Michael Aranda.
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