WINDHAM — The vice president of the Highland Lake Association told members last week that their lake, which is in Windham and Falmouth, “could be at a tipping point.”

Leaders at the association’s annual meeting gave their members an update on the mysterious bloom that has been temporarily clouding the lake for a few weeks each summer over the past three years. There are signs that the bloom has started again this summer, Vice President Rosie Hartzler said this week.

“We have a problem with too many nutrients,” said Hartzler at the July 20 meeting at the Cornerstone Assembly of God Church.

Over-development and runoff from properties could be contributing factors, she said, and the lake could be at “a tipping point.” 

“We have an unprecedented situation in Highland Lake. We’ve never been confronted with the phenomenon that we’re facing,” Hartzler told 60 to 70 people in attendance.

The association has been ramping up its usual water testing and working with researchers, including local college students, to understand the bloom and pinpoint the cause. All indications are that the bloom is not toxic, according to the association.

“Yes, we’ve seen algae blooms before,” said water tester Keith Williams, who has studied the lake for decades. “These guys are different. They’re biologically very different.” 

The association has suspected that the bloom is a form of cyanobacteria, also known as blue-green algae. Thanks to research from students at the University of Maine, they may have evidence linking a particular suspect to the crime – or at least part of the crime. 

Rachel Cray, a rising senior at USM, spent months working on a Highland Lake cyanobacteria investigation project with two of her classmates. And through their work, they were able to identify synechococcus, a species of cyanobacteria, in summer sample data from the lake. 

“We did the equivalent of fingerprinting,” explained Cray, who attended the meeting with a poster board of her group’s findings and answered questions from association members prior to the presentation. 

While the discovery is another piece to the puzzle, the student also noted investigators cannot definitively conclude that synechococcus is the specific cyanobacteria causing the bloom. 

Hartzler pointed out that cyanobacteria are very common – the real question is, what is throwing the lake out of balance and causing the cynaobacteria to bloom each summer. 

Hartzler said erratic weather – including storms that can cause erosion, is the “wild card” in understanding what’s happening at the lake.

One question from the audience was why other lakes haven’t seen the same problem if weather changes are such an important factor. 

Tom Bannen, outgoing lake association president, responded that all lakes are unique, and that Highland Lake may have “extra stresses” from being so close to Portland. 

“It has it’s own characteristics, it has its own chemistry of the sub-soils and the sediments,” he said.

Bannen said the group still has questions to answer and that the project is being called a “discovery and recovery” effort to understand why Highland Lake is different from other lakes. 

Other questions from the audience probed the possible impacts of factors such as the reintroduction of alewives (a type of herring) in the lake, the use of fireworks in the watershed, and proposed future development projects near the lake.  

Karen Wilson, an associate research professor at the University of Southern Maine, was also present to answer questions. She is leading a project to understand the role alewives are playing in the Penobscot River estuary following dam removal on the river. 

Wilson said the relationship alewives may have with the Highland Lake bloom, if any, is still unclear. “It’s really hard to say if alewives are causing this,” Wilson said. “but they don’t cause it in other lakes, so what’s going on?”

Wilson said to determine the answer to that question, she and other researchers are trying to collect more data. 

As the lake association continues efforts to work with researchers and learn more about what’s happening, it also has new faces on the board after several current members termed out and others were elected at the meeting. 

Scott Parolin, one of the new board members, said he has more to learn about the bloom and will be working with the rest of the group to “see we what we can do to illuminate the issue.” 

Bannen’s term may be over, but he plans to continue in his role on the water quality committee and as a water tester. 

“We obviously have a lot more of that to do,” Bannen said. 

Hartzler, who has served as vice president and remains on the board, also said the organization is trying to be better about getting the word out to its members electronically.  

“We as a Highland Lake Association want to acknowledge that we haven’t always done the best on keeping you in touch, and we’re going to really make a concerted effort to use a little more upgraded type of conversation, too,” she said.  

Matt Junker can be reached at 781-3661 ext. 123 or mjunker@theforecaster.net. Follow him on Twitter: @MattJunker.

A view of Highland Lake from the boat launch in Falmouth.