Efforts underway to limit fertilizer use, curb dangerous algae blooms in lakes & ponds

Dozens of ponds and lakes around the state are closed right now due to dangerous algae blooms.

Look closely at the surface of Santuit Pond in Mashpee, and bright green specks floating on the water are clearly evident. That’s cyanobacteria to scientists but is generally referred to as algae by the rest of us.

Whatever it’s called, when it’s too plentiful, it upends the natural ecosystem of a body of water and puts it off-limits to people and their pets. Santuit Pond has been closed since May.

“The prevalence of algal blooms that are potentially toxic to humans and pets has been more widespread, for longer portions of the season, at a greater level of toxicity,” explained Andrew Gottlieb, the executive director of the Association to Preserve Cape Cod, a non-profit that monitors water quality.

Cape Cod has been hit particularly hard by the algal blooms, according to Gottlieb.

“Because we live on a sandbar, because our soils are particularly porous, whatever we put in the groundwater and septic effluent, wastewater effluent, whatever we put on the ground in terms of fertilizers and pesticides, find their way through the ground, into the groundwater and show up in our waterways,” he said.

The high levels of nitrogen found in many popular fertilizers are like steroids for algae. That prompted the Mashpee town manager to send a letter to homeowners last month, pleading with them “to stop the application of fertilizers on grass and landscaped areas.”

Two Cape Cod legislators recently filed a bill on Beacon Hill to give more local control to communities when it comes to curbing the use of fertilizers.

“Eliminating them by themselves is not sufficient to solve the problem,” Gottlieb said. “But it’s an easy no-cost thing that we can all do.”

Growing a lush lawn or a colorful garden without fertilizer isn’t easy but it can be done. Tess Matthews, the garden/nursery manager at Allandale Farm in Brookline, said a good way to start is by getting a soil test.

“That way you can really see what nutrients your soil is lacking, perhaps has too much of, and then you can tailor the treatment of your soil to those results, instead of just using a generic fertilizer,” Matthews said.

Matthews recommends the lab at UMass Amherst. Another suggestion she has is to use native plants, which are more in tune with the local environment and need less help to grow.

Matthews also said to consider planting ground cover, like creeping thyme, instead of grass.

Finally, she said people who believe they still need to fertilize should use an organic slow-release product because more of the nutrients end up in the plant and not running off.

Gottlieb said ponds and lakes are warming with climate change. That’s something algae blooms like and, he said, raises the stakes for timely action.

“We can see the result of what’s happening in our waterways,” Gottlieb said. “We look at it and say if a green lawn gets you a green pond, is that really what’s in the best interest of society?”

The Association for the Preservation of Cape Cod has a free interactive map that makes it easy to check the status of specific locations.

Boston 25 News reached out to the National Association of Landscape Professionals and they provided this statement:

“As an industry, we are committed to working with other organizations and governing bodies to improve water quality. Industry professionals are stewards of the environment who are trained and licensed to use the most appropriate tool to manage turfgrass that creates healthy backyards, parks and public green spaces that the residents of Massachusetts enjoy. Healthy turfgrass benefits the environment by producing oxygen, cooling the surrounding areas, and by sequestering carbon.

“The turfgrass systems that make up our lawns play an important role in the filtering of multiple environmental pollutants, including nitrogen, before it reaches ground and surface waters. Fertilizers are a tool that allows grass to filter pollutants.”