Aquatic ecologist introduces DIY zebra mussel detection
By Crystal Dey / A,exandria Echo Press
Spring has finally arrived in Minnesota. Soon lake lovers will be setting their sights on scenes of summer: boating, skiing, canoeing, kayaking, swimming – and, of course, the emergence of watercraft inspectors patrolling for zebra mussels.
Residents of Douglas County have grown mindful of what goes into and comes out of area waters. But, if you really love lakes, you’re going to need scuba gear and a PVC pipe.
Aquatic ecologist Dr. Darby Nelson shared insights on what has become of waters in Minnesota, Canada and New England at the Latoka Lake Property Owners Association annual meeting on Saturday at LaGrand Town Hall.
“It’s great to see groups like this forming,” Nelson said of the association. “We’re not going to beat the zebra mussels without them.”
Nelson began observing aquatic ecosystems during his first paddle boat voyage as a child. Since that time, he has served in the Minnesota Legislature, taught at Anoka-Ramsey Community College and written a book on lake deterioration. While in the state House of Representatives, Nelson served on the environment and natural resources committees, among others, between 1983 and 1988.
Nelson said that nationwide, 43 percent of surveyed lakes and 80 percent of urban lakes have substandard water quality. When Nelson decided to write a book on the topic, he knew he had to delve deep to find out why drastic changes are occurring, so he bought scuba gear and started exploring.
“I gotta get down there,” Nelson thought.
Nelson was in search of an answer to why lakes people used to be able to see the whites of their toes in as kids are so murky now that people can barely see to mid-thigh. One explanation is concentrations of phosphorus and blue-green algae.
“It [algae] turns lakes into pea soup.”
Dr. Darby Nelson
Nelson said phosphorus is present in all cells, that without phosphorus, there is no life. Too much phosphorus, however, will stimulate a sequence of events that leads to growth of algae, Nelson explained.
“It turns lakes into pea soup,” Nelson said.
Through his exploration, Nelson met a veterinarian who told him of a disturbing incident. A dog died a “gruesome” death within hours after lapping up lake water that contained high concentrations of blue-green algae. Some types of algae will produce a toxic chemical that prevents other organisms from eating it, making it poisonous to humans and animals.
Ironically, animals contribute to the toxicity through shoreline runoff from farmland. Nelson said when it rains, urine-carrying phosphorus runs off farmland into lakes, making the water no longer viable for human recreation.
Nelson said a 50-foot buffer of land from the shoreline would keep chemicals from causing such a problem. He added that many farmers are getting the message and taking proactive steps toward a common goal of clean water.
Erosion, leaf bags and unbuffered, developed shoreline are also contributors to deterioration of lakes, Nelson said. Natural shorelines are raw buffers that filter what enters water systems. Nelson said people have difficulty understanding what they don’t see. People see the tall trees and rough floor of the forest but can’t see past the placid sheet atop a lake.
“Different perceptions produce different behaviors,” Nelson said.
“It’s a simple, cheap way of getting a handle on where zebra mussels are.”