AUBURN — Twin Cities water quality officials may not be able to halt a fish-killing algae bloom in Lake Auburn now, but they can test water quality and consider long-term solutions.

“We want to do supplemental data collection above and beyond what our staff can do,” John Storer, superintendent of the Auburn Water District, said. “It’s critical to get ample data during the water turnover period. We don’t want to miss an opportunity to really see what is going on.”

District and state officials said an algae bloom in the lake is starving the deepest waters of oxygen, killing lake trout.

Storer will brief district commissioners about Lake Auburn water testing options at a special meeting at 4 p.m. Thursday at the district’s offices, 268 Court St.

On Wednesday, Storer and Scott Williams, executive director of the Maine Volunteer Lake Monitoring Program, explained the science behind the algae bloom to members of the Lake Auburn Watershed Protection Commission.

Like Lake Auburn, many Maine lakes and ponds have different water levels segregated by temperature. Water mixes and moves among those levels during the spring and fall, but doesn’t mix during winter and summer temperature extremes.

During the summer, sun-warmed water stays at the top, where it gets oxygenated by the wind. The colder water at the bottom of the lake doesn’t mix so new oxygen doesn’t reach the bottom.

Williams said warm temperatures this spring and summer are behind the algae bloom. Warm early spring temperatures extended the algae growing season and hot summer temperatures supercharged it. Combined with heavy June rainstorms, which eroded the lake’s shoreline and brought phosphorus-rich soils into the water, the algae had an optimum growing environment.

The algae dies and sinks to the colder parts of the lake, where it decays and eats up oxygen in the already oxygen-starved environment.

It’s deadly for the lake trout that live in the deepest, coldest parts of the lake. Water Quality Manager Mary Jane Dillingham said at least 50 fish were killed and washed up on shore but more could have died and stayed in the deep water.

Colder air temperatures that can push surface water down and oxygenate deeper levels are the only thing that will cure the current problem. Lake Auburn’s water levels usually begin mixing in November.

“It’s a long turnover because Lake Auburn is such a large body of water,” Williams said. “But between now and the time of the complete turnover, the surface temperature is slowly coming down so those species that prefer cold temperatures may be able to move up and survive in better oxygenated water. So nature is working for us right now.”

That’s why it’s critical to begin testing the lake now, Storer said.

“We are not seeing changing water quality in respect to public health now, but it concerns us for the long term,” Storer said. “If we don’t do something and the algae recurs each year and gets more proliferate, there could be drinking water quality problems.”

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