WINDHAM, Maine (AP)   Researchers in Maine say a lake’s recent algal blooms are prompting concerns over the health of the body of water.

Beginning in May, water quality tests will begin at Highland Lake in Windham and Falmouth, after a mysterious algal bloom has reappeared every July for the last four summers. The Portland Press Herald reports the nonprofit Highland Lake Association and other parties will host a public forum March 21 about the health of the lake.

Officials say there is no evidence that this bloom is toxic, but it causes a pervasive and noticeable cloudiness in the water.

Association President Rosie Hartzler says she believes the cloudiness is caused by an increasing level of phosphorus in the water.