Susan Knight (ctr), accepts her award from Chancellor Ward (rt) and Carroll Heideman (lt)
Last Thursday, UW Chancellor David Ward hosted a reception for the winners of the 2012 Academic Staff Excellence Awards. Susan Knight, Trout Lake Station’s interim director and outreach specialist, was one of the eight award winners invited. Susan won the Robert and Carroll Heideman Award for Excellence in Public Service and Outreach and the CFL couldn’t be prouder of her.
Susan Knight shows visitors to Trout Lake Station's 2011 Open House how to ID milfoil
CFL director, Steve Carpenter, calls Susan the “friendly and highly informative face,” of both the CFL and UW-Madison in northern Wisconsin. Susan works hard to both keep Trout Lake Station humming along, as well as educate residents and schoolkids about limnology. Her passion is aquatic plants and, via formal workshops, school programs, or at CFL open houses, she’s making sure fans of Wisconsin’s freshwater ecosystems know their aquatic macrophytes one demonstration at a time. When she’s not fulfilling the Wisconsin Idea and engaging residents in learning about their freshwater surroundings, Susan is busy working on her research in northern Wisconsin lakes.
Center for Limnology grad student, Gretchen Hansen, took this video from a past summer’s field season up in Vilas County. While we’ll honor the tradition of fishermen not sharing their favorite spots, it’s safe to say smallmouth bass are doing quite well in this particular lake. Watch as one bass gets aggressive while Gretchen tries to collect rusty crayfish for her research. She says opportunistic bass would often grab her “samples” before she got a handle on them. Not this time, though!
The view along the Mendota shoreline shows the lake in its Spring "clear water" phase Photo: Adam Hinterthuer
If you head down to the shore of Lake Mendota today, you’ll notice you can see right down to the bottom. In fact, the current Secchi reading is seven meters, meaning you can get a clear view of Lake Mendota’s depths more than 20 feet down.
At first glance, it might seem that there’s just not much going on down there, but Lake Mendota is actually teeming with life and right in the middle of an algae bloom.
So what gives on the clear water?
The secret to our currently crystal-clear lake is a tiny zooplankton called Daphnia pulicaria.
While conditions are ideal for some species of algae, like fast-growing diatoms, to thrive, the current cool, highly-oxygenated water is also perfect for Daphnia pulicaria, which are voracious grazers of these kinds of algae.
Daphnia pulicaria Photo: The Wilson Lab at Auburn University
According to CFL research specialist, Ted Bier, this kind of algae means good eats for daphnia and, right now, “they’re gobbling it up as fast as it’s growing.”
Bier says that, in its current state, the lake’s food web is humming right along. Nutrients in the water are consumed by the algae, which are then eaten by Daphnia that then become food for fish, efficiently passing nutrients right up the chain.
But, Bier says, there’s no way to know how long it’ll last. “Two years ago clear water only lasted 36 hours,” he says, thanks to a big rainstorm followed by baking temperatures. “Last year it was two weeks. We’ve had it last as long as two months.”
From left to right: water samples from March 15, April 1 and April 15 show the spring daphnia pulicaria population bloom in Lake Mendota Photo: Adam Hinterthuer
The current clear-water state is happening a bit earlier than average. Bier’s been taking samples each spring for ten years and the first big lake clearing is usually sometime around mid May.
Thanks to this year’s early lake warming and the last couple of weeks of cool, windy, dry weather – conditions are perfect for the annual early algae bloom and subsequent daphnia pulicaria feast. But, if we have a week of high temperatures or a big rain event that flushes a lot of nutrients into the lakes, a different kind of algae, called blue green or cyanobacteria, will begin to take over and we can kiss the clear water phase goodbye. Daphnia just don’t graze on blue green algae with the same relish and head to cooler, deeper waters once the lake warms.
Whatever window of clear water we do get this year, we can thank a little tiny zooplankton that’s a crucial component to our lakes’ water quality and is currently teeming right before our eyes – even if we can’t quite see it.
Check out this new trailer for a series of short films chronicling the research being done as part of the National Science Foundation’s Long-Term Ecological Research program (LTER). You may recognize some shots of Center for Limnology equipment, as we conduct the Northern Temperate Lakes LTER research right here in Wisconsin!
The video was made by a non-profit called Freshwaters Illustrated. Their mission is to promote aquatic awareness through video, photography and film. Beautiful stuff!
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: