Pond scum: Cyanobacteria reports come at alarming rate this year

It can appear as a streak of color, floating mats, scum, or cloudy water, as if a can of greenish paint had spilled into the lake. Whatever the appearance, a bloom of cyanobacteria is enough to bring anyone running down the dock to a screeching halt.

These blooms aren’t just off-putting; they have the potential to be dangerous, as cyanobacteria can — but doesn’t always — release toxins into the water that are harmful to humans and their pets. More instances of cyanobacteria blooms have been reported to the state Department of Environmental Services than ever before.

“It has been a record-breaking year this year already,” said Kate Hastings, coordinator of the program at DES that monitors hazardous cyanobacteria blooms. She said the state issued its first advisory this year May 15, earlier than any other year on record. DES reported six advisories in May, besting the previous record of that month by one.

It’s a troubling trend. Cyanobacteria, though one of the oldest organisms on the planet, is harmful to aquatic animals as well as humans and dogs, as the decomposition of algal blooms can deprive the water of oxygen, resulting in fish deaths. It also has an economic impact, as the degradation of lake and pond quality threatens the value of waterfront property, and could depress tourism to such water bodies.

The people tracking this problem are hopeful educational campaigns will help reduce the local causes for the apparent increase in blooms, while an up-to-date advisory program will help residents and visitors recreate safely and confidently in the Lakes Region’s enduring attractions.

One for the books

“We have already broken the record in June,” Hastings said, speaking at the beginning of the week. She noted the previous record of nine advisories was set in 2018, and again in 2019. “We’ve issued 14 already, and we’re not done yet.”

It’s been an unusual year, to say the least. “Definitely I would use the word ‘unprecedented,’” Hastings said. The state has been collecting data about cyanobacteria blooms for 20 years.

What’s behind such an “unprecedented” year? The exact cause is somewhat murky. Hastings said the state’s advisory program is “very response-based,” meaning action from the state begins with reports from citizens. As more people become aware of cyanobacteria, and what it can look like, more reports are likely to follow — even if the true number of blooms remains constant.

“I think more people are learning about this program. I think getting more attention means more people are aware, and we’re getting more reports,” Hastings said.

However, it’s also true that factors known to promote algal growth are increasing.

“Two major factors are climate change and increasing nutrients into our water bodies,” Hastings said.

Climate change’s impact, with regard to cyanobacteria, comes in two forms. The first is milder winters, which result in shorter periods in which lake and pond surfaces are covered in ice. The sooner the water body surface is exposed to the sun, the sooner algae can start growing.

“This past winter, we did not have long periods of ice cover. We have a longer [algal] growing season, our lakes stay thermally stratified for longer,” Hastings said. “And in New England, we’re also seeing changes in precipitation patterns.”

Those precipitation changes are the second impact of climate change. The region is seeing fewer rain events over the course of the year, but with heavier rainfall amounts in each storm. That matters because the ground can only absorb so much rain at one time. When a lot of rain falls at once, the extra rain runs over the top of the ground, picking up residual fertilizers and naturally occurring nutrients as it flows into storm drains, which generally speaking, empty directly into local waterways.

These rainfall events are exacerbated by poor watershed practices: under-maintained or outdated septic systems, more and more of the landscape being covered by impermeable surfaces, and property owners who are more concerned with the health of their lawns than that of the watershed.

Local problem

“Cyanobacteria exist, and have existed for billions of years. There is cyanobacteria in the Arctic, in volcanoes. They are all around us in natural background levels,” said Bree Rossiter, conservation program manager at Lake Winnipesaukee Association. “The problem with cyanobacteria is that when they are fed by excess nutrients and they proliferate to a bloom state.”

The chief culprit is phosphorus, a chemical commonly used in fertilizers, but also associated with leaky septic tanks. Phosphorus can collect in soil along shorelines, or in the sediment at the bottom of lakes or ponds, and can be stirred or splashed back into the water by powerboats that throw wakes too near to shore, or in shallow waters.

Organizations such as LWA have been advocating for years for conscientious boating practices and property management.

“I know we were talking about it 10 years ago, but it’s one of those things that now, you can visually see more of these blooms happening. It’s raised greater awareness,” said Pat Tarpey, LWA president. “Bear Island had a bloom in 2011, then over in Wolfeboro, Winter Harbor had a bloom in 2018, and that really spurred action.”

Wolfeboro responded by forming a town cyanobacteria committee, and such actions give Tarpey optimism that the issue can be managed, if not eliminated.

“It’s certainly going to take a lot of time. This didn’t happen overnight,” Tarpey said, noting the current levels of phosphorus in Lake Winnipesaukee are three to four times what they would be naturally. “The only way to manage this on Winnipesaukee is to manage the nutrient loading. There’s no quick fix.”

If greater public attention is necessary to manage the problem, then an increased amount of reporting this year could be seen as a good sign.

Some of those early advisories this year were on Lake Wentworth and Crescent Lake, both of which drain into Lake Winnipesaukee. Both advisories have since been lifted.

Julie Brown, executive director of the Wentworth Watershed Association, acknowledged that nutrient loading is a concern, and climate change is “definitely a factor,” but the early reports this year shouldn’t be cause for panic.

“We know more now, we know what we’re looking for,” Brown said. “It might have been present for years, and people didn’t know what they were looking for.”

As Brown has been informing her association about the bloom, she’s been trying to disseminate information without spreading hysteria.

“Lake Wentworth, Crescent Lake, they are known to be clean, healthy water. The water quality [of the lakes] are the highest possible quality. I don’t want to be communicating doom and gloom,” Brown said. “Blooms happen. As we know more, we’re telling people more.”

Yet, such reports also have the effect of getting attention. Brown would like to use that attention to further inform the public.

“The message should be about not putting chemicals on their land,” she said. That’s true whether or not a piece of property is directly on the waterfront.

“Taking actions throughout all watersheds, everything leads to the water,” Brown said. “We know more, it’s concerning. As climate change continues to affect waterbodies, we’ll see more of this.”

Tools for water lovers

As the picture surrounding cyanobacteria comes into focus, more tools are becoming available, both for experts and the general public.

Last year, Gov. Chris Sununu signed into law a bill that mandated DES to create a statewide cyanobacteria plan, due to be finalized this fall.

DES has already introduced a trio of new tools to empower the public. One is an online portal for reporting possible cyanobacteria blooms, another is a weekly newsletter that provides updates on cyanobacteria warnings throughout the state, and a third is the interactive “Healthy Swimming” map that shows where there are any current warnings or advisories, both for cyanobacteria as well as fecal bacteria. All of these are available at des.nh.gov.

The Lake Winnipesaukee Association offers programs to educate landowners how to landscape with water quality in mind. Rossiter also publishes a weekly newsletter about local advisories. Visit winnipesaukee.org for more.

Brown, at the Wentworth Watershed Association, said the best step for any concerned person might be to find an association that focuses on their favorite water body.

“The biggest takeaway is for people to join their lake association,” Brown said. “Membership matters. Listen to state advisories, and volunteer. Volunteer organizations do 90% of the work in this state, especially environmental work.”