Limnology in Action: Long-term Research, Long-term Learning

By Aisha Liebenow
Whether you’ve graduated from high school, have a B.A, or spent several years plugging away at a PhD, I hope your education didn’t stop with your degree. Active learning is so important in keeping your mind at the top of its game, and that’s why I admire the Wisconsin Alumni Association (WAA), and how it provides ample opportunities for its members to continue exploring our world.

Alumni gathered in our (thankfully) air-conditioned Tug Juday Conference Center. Photo: A. Liebenow
Alumni gathered in our (thankfully) air-conditioned Tug Juday Conference Center. Photo: A. Liebenow

Last Thursday we had the pleasure of welcoming the WAA Lakeland Badger Chapter to Trout Lake Station (TLS) for an afternoon of limnology, scientific inquiry, and yummy snacks.

As the alumni trickled in, TLS director Tim Kratz greeted them in our new Tug Juday Conference Center. Everyone filled their plates with fruit, cheese, and crackers and scattered themselves around the room. After they’d settled down and made their introductions, Tim gave a presentation on the storied history of the station and described the research conducted here and the goals that the station encompasses in its daily work.

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A zooplankton tow! To which its proper use was demonstrated by TLS director, Tim Kratz. Photo: A. Liebenow

The Lakeland Badger members were then led on a tour of the station, meeting working researchers and undergraduate assistants along the way. They even learned how to use a zooplankton tow! The tour was followed by a field trip to Crystal Lake, where the Crystal Lake Mixing crew amiably awaited with their boats and oars (Crystal is a no-motor lake), to get the alumni up close and personal with the GELI mixing system. It was a gorgeous day to be on the water.
The wonderful faculty, graduate students, and undergraduates alike were wonderful helpers as they directed the boats out onto Crystal Lake
The wonderful faculty, graduate students, and undergraduates alike were wonderful helpers as they directed the boats out onto Crystal Lake

Beautiful weather aside, the best thing about the entire afternoon was that the alumni never stopped asking questions. They never stopped wondering or wanting to know more, and fully embraced the pursuit of knowledge.
Forever students, and Badgers no less.
It puts me in further awe to think that these alumni were once students at UW-Madison. Like me, they may have worked at an internship or campus job, trying to make their way through school and get the most out of the acclaimed ‘undergraduate experience’. They survived, and succeeded, and today they continue their education outside of the classroom. As active alumni, they are able to follow the happenings at their old stomping grounds, and participate in events like this one held at Trout Lake. Their learning experience carries on, just as our learning experience at TLS carries on in our long-term research.
Noah Lottig, the site manager for our North Temperate Lakes – Long Term Ecological Research (NTL – LTER) survey, was my guide in understanding the importance of long-term research. He explained, “things that happen in lakes, happen slowly, and out of normal scopes of a graduate thesis research project time-frame.” Because of this, there was no mechanism to study long-term change until LTER was established by the National Science Foundation (NSF) in 1981. NTL-LTER was one of 6 initial LTER sites.
Undergraduate and BASE crew member, Caitlin McCleavy, measures the oxygen levels in the water at one of the buoys at our LTER site. Photo: A. Liebenow

Since then, for over 30 years, researchers have monitored 7 bodies of water in the Northern Wisconsin Area – Trout Lake, Trout Bog, Crystal Lake, Crystal Bog, Allequash Lake, Big Muskellunge Lake, and Sparkling Lake. In this way, we have been able to track long term change, and can finally dig in to the machinery that is driving that change.
But what does ‘monitoring a lake’ mean? What do researchers actually track on a continual basis? As Noah put it, “if you can imagine it, we measure it.” This includes all chemical, biological, and physical aspects of a lake you could possibly think of, and are measured throughout the year by our wonderful BASE crew. Chemistry, biota, and species composition are all data points within the interlinking web of knowledge that is LTER. And it just so happens, a prime example of how and why all these data are so important can be found right here at Trout Lake.
I have mentioned rusty crayfish before, a pesky invasive species that is known for its detrimental effects on aquatic plants and fish communities, but these effects were not always known. Thirty years ago, rusty crayfish were first introduced to LTER research sites like Sparkling and Trout Lake. And because LTER had been monitoring the lake, they were able to observe the long-term effects before, during and after the invasion. This eventually led to what we know about ‘rusties’ today.
crayfish figure
This LTER figure shows the incline of rusty crayfish (in red), while a trend in the macrophage (aquatic plant) biomass (in green) remains non-existent until around 1995. At that point in time, a dramatic decrease in macrophage biomass is seen, as the rusty crayfish population continues to grow.

Without LTER, years may have passed by with countless graduate students trying to determine a relationship between the changes in the crayfish population and the changes observed at Trout Lake, with no such luck. When looking at the data collected by LTER in small increments of 3-4 years, there might have been no trend at all! (Or would at least have been very misleading) But by expanding the dataset to the full thirty years, we’re then able to see the true influence of this invasive species. This trend, which took 15 years just to be seen, is shown in the figure on the right.
Since 1981, the LTER program has expanded its reach to 24 sites around the world and continues to develop its social relevance. It has grown tremendously as others have seen the benefits of long-term research and, moreover, tracking long-term change.
As a side-note, Fish Crew is here!!! This group of undergraduate students works on fish population monitoring night and day for ~4 weeks. Here a couple of them are seen mending fyke nets for sampling later in the week.

As Sir Isaac Newton stated, “If I have seen further, it is by standing on the shoulders of giants.”
A perfect phrase for any kind of learning, inside or outside the classroom. We cannot all ‘reinvent the wheel’, and therefore must continuously build upon previous understanding. Whether we are a student, an alumnus, or a scientist, we must never stop in our pursuit of knowledge, not just for our own sake, but to achieve a better understanding of the world in which we live.

These are the first-hand ‘Notes from the Northwoods’, as UW – Madison undergraduate student, Aisha Liebenow, dives into the world of science, ecology, and aquatic systems. Follow her throughout the summer in her Northwoods immersion at the UW Center for Limnology – Trout Lake Station in Boulder Junction, WI.