MINOCQUA, Wis. — Researchers who used a thick plastic curtain to divide a northern Wisconsin lake in half have wrapped up their 30-year study.

A Wisconsin Public Radio report (http://bit.ly/18PZLic ) says scientists were using Little Rock Lake, north of Minocqua, to study the effects of air and water pollution.

The researchers left one half of the lake undisturbed. They slowly added acid to the other side to simulate the effects of sulfur dioxide pollution from coal-fired power plants.

Research scientist Carl Watras says the simulated acid rain destroyed the fish population. He says bass eggs began deteriorating on their nests.

He says the acid also produced a dense algae bloom more than three feet thick in some places on the lake bottom.

The experiment led to 130 scientific papers.