Lecture on the Biosphere and Human Impact

Introduction

• Topic: Understanding the biosphere and how human activities drive changes in natural systems.
• Goals: Gain understanding of:
  • What the biosphere is.
  • Interconnections between biosphere biomes.
  • Human impact on the biosphere.

Biosphere and Biomes

Definition

• Biosphere: The layer containing all life systems on Earth, a complex set of interconnected systems.
• Biome: Geographic area defined by specific environmental factors.
  • Types: Terrestrial and Aquatic biomes.

Terrestrial Biomes

• Characteristics: Vegetation varies from brown (low) to dark green (dense).
• Influencing Factors: Precipitation and temperature.
• Examples:
  • Tropical rainforests
  • Savannas
  • Tropical deserts
  • Chaparral
  • Temperate grasslands and forests
  • Boreal forests
  • Arctic tundra

Aquatic Biomes

• Regions:
  • Freshwater: Ponds, lakes, streams, rivers, wetlands.
  • Marine: Oceans, coral reefs, estuaries.

Human Impact on Biomes

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

Biogeochemical Cycles

• Cycles: Carbon, water, nitrogen, sulfur, oxygen, phosphorus.
• Human activities impact these cycles, e.g., acid rain from burning fossil fuels.

Acid Rain

• Formation: From sulfur dioxide and nitrogen oxides combining with water and oxygen in the atmosphere.
• Effects:
  • Aquatic systems: Nutrient pollution, eutrophication, toxic water.
  • Terrestrial systems: Nutrient loss in soil, affecting trees and plant growth.

Regulation and Recovery

• Clean Air Act (1990):
  • Limited emissions of sulfur dioxide and nitrogen oxides.
  • Resulted in reductions of these emissions, less acidic rainfall and waters.
  • Recovery is ongoing due to nutrient absorption in soils and ecosystems.

Homework Assignment

• Task: Write a 1-3 page position essay on a biosphere change topic.
  • Consider power, authority, oppression in natural system changes.
  • Contemplate perspectives of those directly affected by changes.

Additional Resources

• Weekly Podcasts:
  • NPR: "Rivers on Rolaids" discusses acid rain and waterways.
  • Science Friday: Discusses species extinction and environmental impacts.

These notes summarize the lecture's main topics and can be used to review important details about the biosphere, human impacts, and biogeochemical cycles, with guidance for further exploration and study.