Eutrophication is a process where a body of water becomes overly enriched with minerals and nutrients which induces excessive growth of algae. This can result in algal blooms which reduce oxygen in the water by decomposing and can release toxins. Sources of eutrophication include phosphorus and nitrogen from fertilizers and sewage runoff. Long-term eutrophication has damaged ecosystems by decreasing biodiversity and increasing toxicity. Prevention efforts include regulating agricultural runoff and creating buffer zones while cleanup methods involve filtering pollutants.