AP BIOLOGY

Detailed explanation-1: -Most of the human activities responsible for the increase in global nitrogen are local in scale, from the production and use of nitrogen fertilizers to the burning of fossil fuels in automobiles, power generation plants, and industries.

Detailed explanation-2: -Problems with excess levels of nitrogen in the environment 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-3: -High levels of nitrate in water can be a result of runoff or leakage from fertilized soil, wastewater, landfills, animal feedlots, septic systems, or urban drainage. It can be difficult to pinpoint where the nitrate in drinking water comes from because there are many possibilities.

Detailed explanation-4: -Sewage overflows and livestock farming also add nitrogen to aquatic and terrestrial ecosystems. Human activities, primarily those that convert atmospheric nitrogen into more reactive forms, have exponentially increased rates of nitrogen fixation over the years.