DETROIT LAKES, Minn. — Residents outside of Detroit Lakes are seeing the normally clear water of Long Lake clouded by something that hasn't appeared there for over 30 years.

Long Lake has the reputation of being one of the clearest bodies of water in all of Becker County, but this spring, it's gotten a little murky.

A gold, brownish dust seen in the water isn't mud, though — it's diatoms.

"If you didn't have it (or) study it in college or high school biology, you're not familiar with it," said Andy Butzer, an environmental specialist with the Minnesota Pollution Control Agency.

A diatom is a type of single-cell algae which through a perfect recipe of cold water temperatures and wind stirring up the environment has appeared in Long Lake for the first time in decades.

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Butzer says the diatoms truly shine when you look at them up close.

"That's why you should get one of those handy-dandy microscopes and just start looking at a drop of water," Butzer said, explaining that a microscopic look at the diatoms shows the algae cells are actually covered in a crystal-like translucent material.

"It’s silicon dioxide, which is used to make glass," Butzer said. "Diatoms are actually beautiful because of that glass structure — it's amazing . . . I invite anybody to go online and look at diatom images because they're very special."

As the summer goes on and water warms up the diatoms will be pushed out of the lake by other types of algae and soon enough Long Lake will return to its normal clarity.

It is safe to swim in the lake because unlike blue-green algae, diatoms are not toxic. And if you do — you'll be swimming with an ancient organism.

"As Carl Sagan would say, they're millions and millions of years old," Butzer said.