RICHMOND — Authorities say a family dog helped searchers find a 2-year-old boy who was lost on a chilly night in a central Minnesota cornfield.

The toddler was playing with siblings outside his home in Richmond last week when he wandered away. The Stearns County Sheriff’s Office says family members called authorities after they failed to locate him as it grew dark.

Sheriff’s Lt. Vic Weiss tells the Star Tribune that searchers could hear a dog barking, then State Patrol troopers in a helicopter used a heat-seeking device to pick up the heat from the dog and the boy. The dog hadn’t left the child’s side.

Weiss says the dog was in protection mode and played a major role in finding the boy about three hours after he disappeared.

Study finds clear lakes can be among the most polluted

DULUTH — A new study says appearances can be deceptive — clear lakes can be among the most polluted.

Scientists have long known fertilizer runoff from farm fields can fuel excessive algae growth, turning lakes the color of pea soup.

But a study of 139 Iowa lakes by the University of Minnesota Duluth and Minnesota Sea Grant finds that when lakes reach extremely high concentrations of nutrients, the water can be surprisingly clear. They found high levels of phosphorous and even higher levels of nitrogen in some.

They concluded that extreme nutrient levels killed the algae in the lakes, similar to how too much fertilizer applied on land