AUBURN — Lake Auburn Watershed officials will fund more than half of the water quality studies they say they need to figure out what caused a late-summer algae bloom.

Members of the Lake Auburn Watershed Commission agreed Thursday to spend up to $163,901 to monitor water levels, test lake bottom sediments and lake-side soil, study varieties of algae in the lake and suggest short-term solutions.

That money will come from the 2012 budget, according to John Storer, superintendent of the Auburn Water District and clerk for the Watershed Commission.

Studies will be done by local water quality staff and by consultants from Massachusetts-based CDM Smith, the Maine Volunteer Lake Monitoring Program, the Maine Department of Environmental Protection and Bates College.

“We’ve had our own staff out there, but our consultants will be out next week,” Storer said. “They’re going out in the watershed and out in boats, collecting sediment samples and doing additional testing. So the big push really starts next week.”

The 2012 work would be paid out of the commission’s sinking fund, usually used to purchase watershed land.

Long-term solutions and public information campaigns — amounting to another $111,009 in studies and work — could be paid from the commission’s 2013 budget.

Water quality officials discovered more than 50 dead trout along the shore or floating close to the shore in mid-September. The largest discovered was a 36-inch trout weighing between 15 and 20 pounds. The other fish averaged around 22 inches long.

Officials blamed an algae bloom for killing the fish. They said that 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 soils into the water, the algae had optimum growth.

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

That lower layer of the lake, where the lake trout live, is already low in oxygen late in the summer. The decaying algae used up available oxygen, suffocating the lake trout.

Lake Auburn is the source of drinking water in Lewiston and Auburn. Storer said the fish-killing bloom doesn’t pose a risk to the lake’s water quality but said the commission does want to find out what caused it so they stop it from happening again.

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