AP BIOLOGY

Detailed explanation-1: -This excess nitrogen and phosphorus can be washed from farm fields and into waterways during rain events and when snow melts, and can also leach through the soil and into groundwater over time. High levels of nitrogen and phosphorus can cause eutrophication of water bodies.

Detailed explanation-2: -Manure contains nutrients, such as phosphorus and nitrogen, and pathogens, including bacteria, viruses and parasites. These pollutants contaminate water resources and reduce recreational potential of lakes and rivers, destroy wildlife habitat, and eliminate drinking water supplies for people and livestock.

Detailed explanation-3: -Excess nitrogen can cause overstimulation of growth of aquatic plants and algae. Excessive growth of these organisms, in turn, can clog water intakes, use up dissolved oxygen as they decompose, and block light to deeper waters.

Detailed explanation-4: -Sewage, livestock waste, fossil-fuel burning, and especially our use of synthetic fertilizer have all contributed to a doubling of nitrogen flows.