Nutrients are used by aquatic plants and microbes (bacteria, fungi) for growth. The two primary nutrients are nitrogen (N) and phosphorus (P), which occur both as dissolved ionic forms and bound in dissolved or particulate organic molecules. The dissolved ionic forms are most biologically available and readily assimilated by stream plants. Nutrient concentrations are normally low in pristine stream waters and higher in streams that are impacted by human activities (for example fertilizer leachate/runoff, wastewater and effluent discharges).

View a factsheet on Nitrogen or on Phosphorus