Aquashade in the water will decrease the growth of primary productivity in Ward lake.
Ryan Batt dips a bucket into the lake, and pulls up a quarter-gallon of… Gatorade?
At the surface, Ward Lake is like any small bog: tall trees and sedges are reflected on the dark surface and beaver-gnawed branches stick out at odd angles. Looking down into the water, the lake doesn’t seem that remarkable. But inside the white gallon bucket, the water is sapphire blue, like jell-o or a sports drink. This summer, Batt is turning a lake blue.
The process that Batt, a UW-Madison graduate in CFL director Steve Carpenter’s lab, is using in his experiment is actually very common. In fact, if you have ever seen a golf course pond, chances are you have seen the effects of adding Aquashade to the water. It is a concentrated liquid formula that is similar to food coloring, or blue dye. It is used in lakes and ponds to block light rays from penetrating deep into the water, therefore reducing photosynthesis. In other words it keeps algae from growing.
Students sift through trays of sediment and plants, picking out aquatic invertebrates
Zach Lawson’s question is greeted with incredible enthusiasm. It is all-hands-on-deck in the wet lab and, today, everyone is sorting bugs.
Ten undergraduate students crowd around two small tables, armed with small plastic sampling bottles and metal tweezers. They meticulously sift through plastic tubs of sand, muck and aquatic plants, looking for any small movements in the water. Suddenly, spotting the slightest flicker, a hand strikes, snatching up a very tiny red worm-like creature. The student yells “I have a diptera!” and Lawson quickly walks over to inspect and label the specimen. The students work for hours, leaving no leaf or rock unturned, and soon the lab is filled with bottles of invertebrates. Continue reading →
A group gathers next to a deflated GELI on the shore of Crystal Lake to hear about the mixing experiment
Over the last three years a group of CFL students, professors and staff have worked on an experiment near Trout Lake Station that, they hope, will eradicate rainbow smelt and restore populations of native fish, like yellow perch, bluegill and largemouth to Crystal Lake. The experiment is finally ready to go.
As the early melt in March sent fishermen and boaters scrambling for their gear, members of the Crystal Lake Mixing project, also hurried to get their equipment in place.
“We flipped the switch [on Wednesday],” says Jordan Read, “and plan to leave it running. So far it’s looking good and things are moving along pretty well.”
PhD candidate, Jordan Read, explains how GELIs will mix the lake
Read, a PhD candidate in civil and environmental engineering at the University of Wisconsin-Madison, is one of the lead researchers on the project. Along with his colleagues, he’s built what looks like an armada of trampolines in the middle of Crystal Lake. They’re called “gradual entrainment lake inverters,” or GELI’s for short, and they’re hooked up to a bank of air compressors on the shore that, when controlled by a central computer, will send GELIs rising to the surface of Crystal Lake and sinking to the bottom throughout the summer.
You can read more and get real-time Crystal Lake data here.
The GELIs were designed to mix the entire water column and prevent Crystal Lake from stratifying this summer. That would keep the cold bottom layer of water from forming and, hopefully, make the lake too warm for the cold-water smelt to survive. The mixing won’t hurt native fish, since they’re all warm-water species.
Rainbow smelt are originally from saltwater habitats. They were brought to Michigan as forage fish for stocked salmon populations and soon escaped into the Great Lakes. Smelt became a popular table fish for some fishermen and researchers think they entered inland Wisconsin lakes via illegal stocking or in nets that hadn’t been properly cleaned.
Zach Lawson describes how the invasive smelt disrupt Crystal Lake's native fish populations
With an estimated smelt population of over 200,000 fish, a sudden die off could be quite obvious. If the experiment is successful, says Zach Lawson, a research assistant at Trout Lake Station, one sign may be dead smelt washing up on the beach.
“It’s a pretty common concern of people,” he says. “But you have to keep in mind that we are out there every morning before 9 am starting work, monitoring and maintaining GELI’s , and sampling. We’re out there every day, so we should be there to see anything that happens.”
And, Lawson says, it would be a short-term problem. A team of students and staff at Trout Lake Station are “on call” all summer to take care of any problems.
In other words, summer undergraduates should have shovels at the ready and wait for the call of – “Clean up on Crystal Beach!”
Watch the video of the creation of the Crystal Mixing project below:
