Sulfur and nitrogen deposition on ecosystems in the United States

Research conducted in the US have confirmed the impact of pollutants such as acidic deposition of sulfur and nitrogen on ecosystem. The documented effects in the US include acidification of lakes and streams, nitrogen saturation of watersheds, modification of forest chemistry, growth, and regeneration. The research studies have also documented the effects of excess nitrogen to nutrient-limited ecosystems and the eutrophication effects include changes in soil and plant chemistry. A monitoring system is established to track progress, access ecosystem response to reductions in acid deposition emissions, and inform future policy development. The studies have also confirmed that additional nitrogen and sulfur reductions emissions are needed to facilitate additional chemical recovery, leading to additional biological recovery.