Mysterious brown foam prompts testing at Lake Mead after dozens of dead carp found

Authorities are investigating mysterious brown foam that showed up on the surface of Lake Mead over the weekend.

Dozens of carp were also found dead in the area.

Southern Nevada Water Authority spokesman Bronson Mack says technicians collected water samples Tuesday in hopes of solving the mystery.

He says tests on samples collected a few days ago by a volunteer turned up normal, but scientists want to gather new samples using more formal methods.

Lake Mead officials on Saturday urged people to avoid the Overton Arm after foam appeared on an eight-mile section of the lake stretching from about the mouth of the Virgin River to Echo Bay.

Mack says his agency continues to test water at its Lake Mead intakes, and it is meeting quality standards.