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Green Lake water samples taken by DNR in continuing search for zebra mussels

Nick Brown, Department of Natural Resources aquatic invasive species specialist, shows water samples taken Thursday on Green Lake in Spicer. The samples will be tested for microscopic zebra mussel larvae called veligers. (Tribune photo by Carolyn Lange)2 / 3
Alex Ipsen, a summer intern with the DNR, helps take the samples Thursday from Green Lake that will be tested for microscopic zebra mussel larvae called veligers. (Tribune photo by Carolyn Lange)3 / 3

SPICER — Equipped with a long, white plankton sieve, plastic bottles and rubb ing alcohol, Nick Brown and his summer intern, Alex Ipsen, collected two murky samples of Green Lake water Thursday in search of veligers, the microscopic larvae of zebra mussels.

Since an adult zebra mussel was found on a dock Monday on Green Lake, the state Department of Natural Resources has been looking for more evidence of a zebra mussel population.

Taking the water samples is a “shot in the dark,” said Brown, an aquatic invasive species specialist with the DNR.

One sample was taken in water about 10 feet deep near the dock on the southeast side of Green Lake where a homeowner said he found the adult zebra mussel.

Another sample was taken farther out, at a depth of about 35 feet.

The sieve, which filtered out anything larger than 80 microns, was filled with a column of lake water.

The green scum that remained was collected in a container at the bottom of the sieve.

The goo was mixed with alcohol and dumped into a bottle and labeled with the GPS location of where the water was collected.

The alcohol will preserve any plankton in the bottle, which was put in the mail and sent to the DNR in St. Paul, where the samples will be tested and examined for signs of zebra mussel larvae.

The results of that test, as well as additional searches for adult zebra mussels around the lake, could be a factor in what action the DNR takes next on Green Lake.

Brown said the decision on whether or not to designate Green Lake as infested with zebra mussels will be made by experts in St. Paul.

So far, the DNR is waiting to make that designation until they see what Brown’s continued investigation turns up.

Carolyn Lange

A reporter for more than 30 years, Carolyn Lange covers regional news with the West Central Tribune.

(320) 894-9750