Dr. Mark Heilman, vice president of environmental restoration at SePRO, highlights how phosphorus from lawn care contributes to harmful algal blooms in US lakes and rivers. In a podcast episode, he shares successes in restoring polluted waters and stresses the importance of prevention over remediation. The discussion covers invasive species and climate impacts on water quality.
Every summer, algal blooms turn cherished US lakes toxic, as seen in Lake Erie where half a million people in Toledo lost drinking water, and Florida's red tide causing billions in tourism losses. Dr. Mark Heilman, with two decades at SePRO, has helped restore 1.4 million acres of polluted lakes and wetlands across North America. At Moses Lake in Washington, his team's efforts achieved a 42% reduction in harmful phosphorus levels, safeguarding $300 million in annual tourism revenue.
Phosphorus from fertilizers and runoff fuels algae growth, likened by Heilman to Miracle-Gro, leading to blooms that deplete oxygen, harm aquatic life, and release toxins causing liver damage, neurological issues, and death. US Environmental Protection Agency reports indicate rising numbers of lakes with poor water quality and more frequent, intense harmful algal blooms. Even routine lawn care plays a role: a bushel of grass clippings carries about a tenth of a pound of phosphorus—equivalent to a box of Miracle-Gro fertilizer—and can produce up to 50 pounds of algae in waterways.
Restoring affected waters requires a surgical approach to the ecosystem, involving water quality assessments, community involvement, and multi-year programs. The climate crisis worsens the issue, with warmer temperatures promoting cyanobacteria. Invasive species like hydrilla, described as 'disturbance specialists,' thrive in these changes and outcompete natives. Heilman emphasizes prevention: 'It’s easier to prevent, takes less resources and investment to prevent them than to actually try to resolve them once these problems are in the environment.' The episode, originally aired on September 15, 2025, is available with a transcript on Earth911.