Lecture on the Biosphere and Human Impact

Introduction

• Discussion on the biosphere and human-driven changes in natural systems.
• Goal: Understand the biosphere, interconnected biomes, and human impacts.

What is the Biosphere?

• Definition: The layer of all life systems on Earth.
• Complexity: Made up of interconnected systems.

What is a Biome?

• Definition: Geographic area defined by specific environmental factors.
• Types:
  • Terrestrial biomes (land)
  • Aquatic biomes (water)
• Vegetation Scale: Ranges from brown (low vegetation) to dark green (high vegetation).
• Influencing Variables: Precipitation and temperature.
• Examples:
  • Terrestrial Biomes: Tropical rainforests, savannas, deserts, grasslands, forests, tundra.
  • Aquatic Biomes: Freshwater (ponds, lakes, rivers, wetlands) and Marine (oceans, coral reefs, estuaries).

Human Impact on Biomes

• Examples:
  • Rainforests: Deforestation, biodiversity loss.
  • Oceans: Plastic pollution, overfishing.
  • Rangelands: Overgrazing, habitat loss.
  • Savannas: Land use changes.
  • Wetlands: Destruction for development.
  • Deltas: Nutrient pollution from fertilizers.

Biogeochemical Cycles

• Purpose: Understanding nutrient movement in life systems.
• Types:
  • Carbon cycle
  • Water cycle
  • Nitrogen cycle
  • Sulfur cycle
  • Oxygen cycle
  • Phosphorous cycle
• Human Impact: Varied impacts including acid rain.

Acid Rain

• Formation: From sulfur dioxide and nitrogen oxide (fossil fuel combustion).
• Effects:
  • Aquatic Systems: Oxygen depletion, eutrophication, toxicity.
  • Terrestrial Systems: Nutrient loss from soil, stress on plant growth.

Environmental Policies

• Clean Air Act 1990: Reduced sulfur dioxide emissions by 88% and nitrogen oxides by 50%.
• Outcome: Less acidic rainfall, ongoing recovery in ecosystems.

Homework Assignment

• Task: Write a 1-3 page position essay on a biosphere change.
• Focus: Role of power, authority, oppression in biosphere changes.
• Considerations: Impact on decision-making and policy.

Additional Resources

• Podcasts:
  • NPR: "Rivers on Rolaids"
  • Science Friday: Firefly populations discussion.

These notes provide an overview of the key points discussed in the lecture on the biosphere and human impact on natural systems.