Nutrient runoff

Flowers grown on inexpensive floating platforms can help clean polluted waterways, over 12 weeks extracting 52% more phosphorus and 36% more nitrogen than the natural nitrogen cycle removes from untreated water, according to our new research. In addition to filtering water, the cut flowers can generate income via the multibillion-dollar floral market. In our trials of various flowers, giant marigolds stood out as the most successful, producing long, marketable stems and large blooms. Their yield matched typical flower farm production. Why it matters Water pollution is caused in large part by runoff from farms, urban lawns and even septic tanks. When it rains, excess phosphorus, nitrogen and other chemicals wash into lakes and rivers. These nutrients feed algae, leading to widespread and harmful algae blooms, which can severely lower oxygen in water, creating “dead zones” where aquatic life cannot survive. Nutrient runoff is a critical issue as urban areas expand,...