Welcome to summer 2024. We’re off to a blistering start.

The heat dome that descended on the eastern U.S. roasted the region with heat indexes topping triple digits in some inland areas of Maine. The early-season scorcher produced the necessary warnings about heat-related illness, but not much has been mentioned about another consequence that too often flies under the radar: Warming water temperatures can exacerbate the threat of toxic algae blooms.

Why should we Mainers worry about toxic algae? Harmful algal blooms are not just a summer nuisance; they are rising in frequency, intensity and duration. Even in Maine.

Warming waters combined with excess nutrient pollution can create a summer stew of harmful algae. Outbreaks can suck the very life out of sensitive ecosystems, with some producing toxins that can sicken humans, kill aquatic life and even be fatal to pets who come into contact with infected water. In severe cases, harmful algal blooms contaminate drinking water supplies and damage livelihoods and local economies. Every state in the U.S. has been impacted, including Maine.

Unfortunately, the combination of heat and harmful algae has become as much a part of the American summer ritual as picnics and beach time. The Gulf of Maine is one of the fastest-warming water bodies in the world. Algal blooms occur in the gulf every year, some producing dangerous neurotoxins that accumulate in shellfish and cause paralytic shellfish poisoning in humans.

Maine’s freshwater lakes, ponds and reservoirs are increasingly at risk for outbreaks of cyanobacteria, commonly known as blue-green algae. We know that cyanobacterial blooms return to the same water bodies year after year, as if on cue.


Lovejoy Pond is among a handful of water bodies designated by the state as having a “very high” risk of toxic algae blooms every year. Sabattus Pond, China Lake and Threemile Pond are also among the repeat offenders. In recent years, some lakes and ponds suffered their very first outbreaks, prompting health advisories and warnings to stay away.

Must we accept this as just another part of our summer scene? The answer is no.

We can and should put more resources into prevention. Every state should establish a comprehensive harmful algal bloom program that mandates routine monitoring and tracking. More states should consider adopting fertilizer application standards and strengthening manure regulations and municipalities should look into upgrading wastewater treatment facilities to ensure nitrogen-based pollutants are not being discharged into waterways. Agencies in charge of tracking outbreaks need more funding and additional resources.

Better management of nonpoint source pollution, reduced fertilizer use, and the creation of buffers to absorb agricultural nutrients and reduce runoff would also make a difference, as would the use of proven technologies and product applications to treat and prevent harmful blooms.

Freshwater bodies, in particular, need more attention and consistent monitoring.

The National Oceanic and Atmospheric Administration and the Environmental Protection Agency do a great job of monitoring ocean and coastal algal blooms, but inland freshwater bodies aren’t getting the attention they need.

Our local bays, lakes, ponds, rivers and reservoirs are treasures that must be protected and conserved for future generations. We must address the threat of harmful algae with science and with vigilance. Our next generation should expect nothing less.

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