Algae Impacts

Nitrogen and phosphorus are part of healthy aquatic habitats. These nutrients support the growth of underwater plants that provide oxygen and habitat for fish and other animals. They also support algae growth, which is a source of food for many fish and shellfish. Aquatic habitats can become unbalanced, however, when too much nitrogen and phosphorus enter the waters. Algae can grow out of control, reducing oxygen levels in the water and blocking sunlight that underwater plants need to grow. Too much algae in a water body can produce bad smells, clog drinking water filters and cause drinking water taste and order problems.

There are many sources of nitrogen and phosphorus, including agricultural livestock waste and fertilizer; fertilizers and pet waste from home yards and gardens; and detergents and soaps. Rain water can pick up these substances and carry them into storm drains and local water bodies. Sometimes, nitrogen and phosphorus can impact waters far from where the nutrients originate.

Viewer Tip: Reducing nutrient pollution at home will help protect waters nearby and downstream.

  • Apply fertilizer and other yard care chemicals only when necessary.¬† Wait for dry weather to apply.
  • Pick up pet waste at home and on walks. Avoid walking pets near streams and other waterways.
  • Use a commercial car wash that filters and recycles water. Or, wash your car on a grassy or gravel-covered area where water can soak into the ground. Use soap sparingly.

(Sources: United States Environmental Protection Agency. “Nutrients: The Problem,” and “Nutrients: Take Action,”

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