Human Impact On Biogeochemical Cycles Worksheet

Human Impact On Biogeochemical Cycles Worksheetsci256 Version 61unive

Using the textbooks, the University Library or other resources, answer each of the following questions in 150- to 300-words. Be sure to provide references for the sources you use.

Your neighbor faithfully applies fertilizer to his lawn to ensure beautiful, healthy green grass. Explain how your neighbor’s fertilizing habit affects at least one nutrient cycle.

Your friend commutes to work every day by driving a standard gasoline-powered car. Explain how your friend’s commute affects one or more nutrient cycles.

Urban areas typically have lots of pavement and compacted soils. Explain how these impermeable surfaces affect at least one aspect of the hydrologic cycle.

Paper For Above instruction

Human activities such as fertilizing lawns, vehicular transportation, and urban development significantly influence biogeochemical and hydrological cycles. These impacts can have both localized and global consequences on ecosystem health and climate regulation.

Fertilizer application by homeowners introduces excess nutrients, primarily nitrogen and phosphorus, into the environment. This practice influences the nitrogen cycle, which is crucial for plant growth and soil fertility. When fertilizer is applied, especially in excess, it often leaches into the soil and groundwater or runs off into nearby water bodies during rain events. This runoff can lead to eutrophication, a process characterized by excessive nutrient enrichment that stimulates dense plant and algal growth in aquatic systems. Eutrophication results in oxygen depletion as decomposing organic matter consumes dissolved oxygen, leading to dead zones where aquatic life cannot survive. This disrupts aquatic ecosystems and affects biodiversity (Carpenter et al., 1998). Additionally, nitrogen from fertilizers can volatilize into the atmosphere as ammonia gas or be converted into nitrous oxide, a potent greenhouse gas, thereby influencing atmospheric chemistry and climate patterns (Galloway et al., 2008).

Similarly, a typical commuter utilizing a gasoline-powered vehicle impacts the nitrogen cycle through emissions. Combustion processes in engines release nitrogen oxides (NOx) into the atmosphere, which are precursors for smog formation and acid rain. Nitrogen oxides contribute to atmospheric nitrogen deposition, which can increase nitrogen levels in terrestrial and aquatic ecosystems, further altering their nutrient dynamics (Davidson et al., 2003). Increased atmospheric nitrogen can lead to soil acidification, affecting plant health and soil microbial communities, and disrupt the natural equilibrium of nutrient cycles.

Urban surfaces such as pavement and compacted soils profoundly modify the hydrologic cycle by reducing infiltration capacity and increasing surface runoff. Impermeable surfaces prevent rainwater from penetrating the soil, which diminishes groundwater recharge—a vital component of the hydrologic cycle. As a consequence, there is more rapid surface runoff, which can lead to increased flooding, erosion, and transport of pollutants into water bodies (Schueler & Herlihy, 2004). This runoff often carries nutrients, heavy metals, oils, and other contaminants, degrading water quality in nearby streams and lakes. The decreased infiltration also reduces soil moisture availability, adversely affecting plant growth and altering the local microclimate.

References

• Carpenter, S. R., Caraco, N. F., Correll, D. L., Howarth, R. W., Sharpley, A. N., & Smith, V. H. (1998). Nonpoint pollution of surface waters with phosphorus and nitrogen. Ecological Applications, 8(3), 559-568. https://doi.org/10.2307/2641256
• Galloway, J. N., Cowling, E. B., & Cosby, B. J. (2008). Reactive nitrogen and the world: A global synthesis. Ambio, 37(3), 239-248. https://doi.org/10.1579/0044-7447(2008)37[239:RNAWTW]2.0.CO;2
• Davidson, E. A., Mauzerall, D. L., Searchinger, T., Dumas, P., & Yodzis, P. (2003). Overcoming the nitrogen dilemma. Science, 301(5637), 1522-1523. https://doi.org/10.1126/science.1084564
• Schueler, T. R., & Herlihy, A. T. (2004). Water quality benefits of urban stormwater BMPs. In Proceedings of the 10th International Conference on Urban Storm Drainage (pp. 1-10).

In conclusion, human activities significantly disrupt natural biogeochemical and hydrological cycles. Fertilizer use enhances nutrient runoff and gaseous emissions, altering ecosystems and contributing to climate change. Urban development impairs natural water infiltration, increasing pollution and flood risks. Understanding these impacts emphasizes the importance of sustainable practices to preserve ecosystem integrity and water quality.