Human Impact on Biogeochemical Cycles

The video discusses the impact of human activities on natural cycles, focusing on the hydrologic, carbon, nitrogen, and phosphorus cycles. It highlights how deforestation, urbanization, and agricultural practices disrupt these cycles, leading to environmental consequences such as erosion, flooding, and increased atmospheric CO2. The use of fossil fuels and synthetic fertilizers further exacerbates these issues, affecting soil bacteria and aquatic ecosystems.

What is one of the main reasons humans have been successful as a species?

• Our ability to adapt to natural environments without altering them

• Our skill in altering environments to meet our needs

• Our reliance on natural cycles without interference

• Our dependence on a single type of ecosystem

How does deforestation primarily affect the hydrologic cycle?

• It enhances transpiration

• It increases groundwater infiltration

• It decreases groundwater recharge

• It reduces surface runoff

What is a consequence of urbanization on the hydrologic cycle?

• Increased surface runoff

• Decreased urban flooding

• Increased groundwater recharge

• Enhanced natural vegetation

What has driven human society for the last 150 years according to the carbon cycle discussion?

• Hydroelectric power

• Nuclear energy

• Renewable energy sources

• Fossil fuel usage

How does deforestation impact the carbon cycle?

• It increases photosynthesis

• It enhances carbon storage in trees

• It reduces atmospheric CO2

• It prevents CO2 removal from the atmosphere

What agricultural practice negatively impacts soil bacteria in the nitrogen cycle?

• Use of organic fertilizers

• Natural pest control

• Soil churning

• Crop rotation

Why are chemical fertilizers used in agriculture?

• To decrease water usage

• To increase soil erosion

• To reduce plant growth

• To supplement nitrogen in croplands

What is a major effect of high-phosphorus fertilizers on aquatic ecosystems?

• They decrease water pollution

• They enhance aquatic plant growth

• They cause nutrient imbalances

• They reduce nutrient levels

How does deforestation affect the phosphorus cycle?

• It carries away phosphorus nutrients

• It increases phosphorus retention in soil

• It enhances phosphorus absorption by plants

• It reduces phosphorus runoff

What is a common characteristic of both the nitrogen and phosphorus cycles?

• Both cycles are independent of agricultural practices

• Both are unaffected by human activities

• Both are enhanced by deforestation

• Both are disrupted by excess nutrients in ecosystems