Barry Kutzen heads out Thursday morning from his home on Middle Range Pond in Poland to conduct water quality tests. Russ Dillingham/Sun Journal

POLAND — In his nearly 40 years as a volunteer lake monitor on Middle Range Pond, Barry Kutzen has never detected an algal bloom — until now.

A couple of weeks ago, Kutzen was conducting his regular water quality tests on the lake when he measured a sharp decline in water clarity.

“I’m sort of spoiled thinking what a wonderful situation we have here with this really beautiful body of water that stayed, despite all of the insults to it, (clean),” Kutzen said. “And then all of a sudden, like a body blow, boom, just like that, in a period of (about a week), it’s gone way down.”

Kutzen can usually see a Secchi disk, a common tool to measure water clarity, until a depth of 20 to 23 feet. But two weeks ago, it was just 16 feet. This week, the visibility dropped to about 10 feet.

The lake, too, has taken on a noticeable green tint, he said.

Scott Williams, the retired executive director of Lake Stewards of Maine, visited the lake last week. He said the algal bloom is likely not a health concern at this time, although it could become one if the bloom continues to grow. Generally, toxic conditions can develop when water visibility hits 8 feet or less.

Barry Kutzen looks through an underwater viewer Thursday morning on Middle Range Pond in Poland. While doing so he lowers a Secchi disk attached to a long tape measure until it goes out of sight. He then pulls it up slowly until it appears again in the scope and looks at the tape measure he is holding on the boat to get a measurement on water clarity. Russ Dillingham/Sun Journal

Still, while it is probably safe for those who drink the treated lake water, he recommends they find an alternative source for now.

And while Middle Range Pond is experiencing an algal bloom, there are no signs of one developing in either Upper Range Pond or Lower Range Pond. The three lakes are connected. Water from Upper Range flows into Middle Range, which flows into Lower Range.

Williams said it is too early to know exactly what caused the bloom, why it is isolated to Middle Range Pond or even the type of algae, although he suspects it is type of cyanobacteria (blue-green algae). A sample of the algae has been sent to the state for testing, and results are expected to become available in a few weeks.

Barry Kutzen uses his depth finder Thursday to locate a specific point on Middle Range Pond in Poland. He has been a volunteer pond monitor for nearly 40 years. Russ Dillingham-Sun Journal

He thinks the bloom was the result of a hot summer and likely worsened by the heavy rain in the area early last week. Heavy rain causes erosion, which helps transport excess nutrients in the watershed into the lake.

When summer temperatures are hot, pond water evaporates, concentrating the nutrients in the water, Williams said. Warm water also takes longer to turn over, starving the bottom of the lake of oxygen and releasing nutrients trapped in sediments, compounding the problem.

In Williams’ and Kutzen’s decades of monitoring, neither recalls an algal bloom growing on Middle Range Pond. Kutzen has lived on the lake for 45 years.

“I’m sitting right out here in the lake right now on a dock, and you would never know, just sitting on the dock, that it’s so bad,” Kutzen said Tuesday evening.

The Secchi disk is seen Thursday through an underwater viewer as it’s lowered into Middle Range Pond in Poland to measure water clarity. Russ Dillingham/Sun Journal

He said he is “hoping against hope” that cooler air temperatures will soon reduce the algae growth in the lake.

Range Ponds Association board member Ken Knight’s family has owned a camp on Middle Range Pond since 1960. As a boy in 1964, Knight remembers an algal bloom caused by a failure in leach fields at the Job Corps site at the top of Poland Spring.

“The lakes turned as green as can be, and you could not see your hand if you stuck it in the water,” he said. “The remedy was the Army Corps came in with air boats and sprayed copper sulfate, which cleared the lake within a day or two, or so it seemed. We have not had a bloom of that magnitude since.”

An algal bloom is a rapid increase in the growth of algae. In severe blooms, algae can make water toxic to humans and fish and deprive the aquatic ecosystem of critically important oxygen.

Williams said scientists are seeing an increasing number of lakes with algal blooms that historically have remained clear, including Middle Range Pond.

He said warmer summers and diminishing ice cover on Maine’s lakes are likely significant drivers of the increasingly common algal blooms.

“The Range Ponds Association is working closely with Williams to determine what is causing the algae bloom,” said association President Bill Williams, who owns property on Middle Range Pond. “We have posted preliminary information on our Range Ponds Association Facebook page. Once we have more information, we will post on the Range Ponds Association website and Facebook.“