LEWISTON — Water-quality studies designed to find out why Lake Auburn’s oxygen levels changed so quickly this past summer could be the responsibility of the Lake Auburn Watershed Protection Commission, according to Lewiston Water District officials.

Public Works Director Dave Jones said the watershed commission will be asked to pay for more studies of the fish-killing algae bloom discovered last month in Lake Auburn.

The lake is the water supply for Lewiston and Auburn.

“We have not had a problem with the water we provide,” Jones said. “But this is an indication that we have an issue with the health of the lake that we need to address. We care about the health of that lake. It’s probably the most valuable resource Lewiston and Auburn have. It’s irreplaceable, so we want to protect it.”

Plans call for a new regimen of water-quality testing, mitigation, planning and public relations to deal with a lake trout-killing algae bloom.

Auburn Water District officials set aside $50,000 last month to pay for their share of testing. Jones said the watershed commission will be asked to pay at their Thursday meeting.

“There are monies set aside that they have access to for land acquisition and protecting the lake,” Jones said. “I think this certainly qualifies as protecting the lake.”

Scott Williams, executive director of the Maine Volunteer Lake Monitoring Program, presented current theories about the algae bloom to councilors Tuesday.

He said warm, early-spring temperatures extended the algae-growing season, and hot summer temperatures supercharged it. Combined with heavy June rainstorms that eroded soil around the lake and brought phosphorus-rich soil into the water, the algae had optimum growth.

As the algae grows and dies, it sinks into the lake, decaying and using up oxygen in the process.

That layer of the lake where the lake trout live is already low in oxygen late in the summer. The decaying algae use up available oxygen, suffocating the trout. Water-quality officials said at least 50 fish were killed and washed up on shore.

Williams said other factors could be behind the change in Lake Auburn. Gloeotrichia, a kind of algae that feeds on the lake bottom, has been found in Lake Auburn. It’s also possible that the algae-feeding nutrients came from the lake bottom, not from spring runoff.

That’s why tests are needed.

“Hopefully, by the time we get through the increased tests and sampling next summer, we’ll be able to document the process at Lake Auburn,” Williams said.

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