Our beloved summer swimming spot, Crystal Lake, was temporarily closed this summer after a dangerous bloom of toxic cyanobacteria underscored the growing toll of climate change on our local waters.
In an email to Newton residents on August 13, Mayor Ruthanne Fuller explained that the Massachusetts Department of Public Health (MDPH) and Newton Health and Human Services (HHS) concluded that Crystal Lake must be closed temporarily due to potential safety hazards.
Cyanobacteria, often called blue-green algae due to its appearance, is the cause of the harmful algal blooms (HABs) we saw in Crystal Lake. These Cyanobacteria HABs or CyanoHABs produce toxins that can cause illness in humans and animals that may come into contact with the water. To stay safe during a bloom, residents are advised to avoid swimming, swallowing the water, or launching boats into affected waters.
CyanoHABs thrive in warm, stagnant water and have benefited from the extended periods of excessive heat and minimal rainfall. As water temperatures increase as a result of climate change, these blooms continue increasing in both their size and duration. The Charles River has had cyanobacteria blooms almost every summer for the last decade. Its longest bloom lasted twelve weeks in 2020! Another byproduct of global warming, rising carbon dioxide levels in the air, also accelerates the growth of cyanoHABs. Since cyanobacteria can float to the water’s surface, they can directly use CO₂, giving it a competitive advantage over other algal species. Additionally, as carbon dioxide increases the acidity of the water, a new environment is created in which many other algae cannot survive in, but CyanoHABs thrive in.
Given the situation on the Charles, groups like the Charles River Watershed Association (CRWA) advocate for stronger stormwater regulations and promote green infrastructure to reduce runoff. Volunteers can become Cyanobacteria Visual Monitors and help identify and track cyanobacteria blooms. These efforts will hopefully reduce blooms in the future and increase the potential to spot them early on.
Crystal Lake has been reopened as the water is now deemed safe. But it’s important to know how to prevent future CyanoHABs, and how to best stay safe when they are in bloom. Even though Crystal Lake is open again, harmful blooms remain an ongoing issue across Massachusetts, with more than 40 lakes and rivers still experiencing outbreaks this season. Before swimming or boating, residents should always check local advisories to make sure the water is safe.
Sources:
www.newtonbeacon.org/crystal-lake-closed-due-to-cyanobacteria/
www.epa.gov/habs/climate-change-and-freshwater-harmful-algal-blooms