Around the Clock Limnology – To Better Understand Our Lakes, Some Researchers Lose a Lot of Sleep

by Cassie Gauthier – Getting to see the sunrise over a lake as I nestle into my sweatshirt in the brisk morning air is one of my favorite things. Another is being in the middle of the lake on a boat as the stars shine brightly over my head. Before this week, I had never experienced both of those beautiful sights within the same 24-hour period. Thanks to David Ortiz, a Ph.D. student working at Trout Lake Station and Cory Vines, a UW-Madison undergraduate student, I witnessed a paired sunrise and sunset on Sparkling Lake.

While I was with them in the boat, all my attention should have been on them – what they were sampling for and how they were collecting their samples. But to be honest, the sky was so beautiful I caught myself getting distracted several times. At one point while the sun was rising, I noticed how focused they were on their work and had to tell them to look to make sure they weren’t missing the beautiful view.

Cory shows off all of the different data the FLAMe collects as it traverses the lake. Photo: Cassie Gauthier

Throughout the boat ride they rarely, if ever, took time to slow their sampling and take in the view around them. I was confused as to how little they seemed to care.

David and Cory are sampling four lakes this summer. They rotate through them every two weeks, visiting two per week. Each sampling period is a 24-hour cycle with five different times they go out on the lake to collect data – sunrise, noon, sunset, midnight, and again at sunrise.

When they are on the lake, they stop in the middle to collect Secchi disc readings, chlorophyll measurements and phytoplankton samples. Then, the rest of the time is spent taking a quick ride around the lake following a grid-like pattern with the FLAMe (Fast Limnological Automated Measurements). The FLAMe sucks in water from the lake and spits it out after collecting a bunch of water quality data such as dissolved oxygen, temperature, nitrate, and many other things. These measurements will help David understand the variability in water chemistry across the lake which are important for the growth of algae, plants, zooplankton, and even fish.

My two trips out on the lake with David and Cory was a chance to learn more and see beautiful scenes. But, for David and Cory – who do this each week – every trip is part of a summer with long work hours and a very scrambled sleep schedule.

While the field work is entirely exhausting, it’s still easy to see how passionate David is about what he might learn from the long hours he’s putting in.

David makes sure the FLAMe is running smoothly for another transect of Sparkling Lake. Photo: Cassie Gauthier

“For years limnologists or lake management crews have only taken one sample in the middle of the day from the middle of the lake and assumed that was a good representation of the entire lake, which is almost never the case,” David says. Lakes have a lot of spatial variability. It’s common for one part of a lake to have clear water that’s perfect for swimming or fishing while another part of the same lake is dark green with algae. “The FLAMe,” David explains, “Is able to sample all the locations across lakes and capture those differences, and, with my project this summer it is also collecting samples over the course of a day.”

While the lakes in northern Wisconsin are mostly clear and great for swimming and fishing, lakes in many other areas are not. David grew up in Iowa and recalls beaches he lived by would often be shut down because of large amounts of agricultural runoff in the lakes fueling algal blooms capable of producing harmful toxins.

Seeing this motivated David to better understand all that is happening in a lake, and he hopes that one day this data will help scientists capture oncoming algal blooms in lakes earlier.

Sometimes for scientists like David, it takes working outside of the typical 9-5 workday schedule, losing a little sleep, and paying less attention to beautiful sunrises to uncover the mysteries they are studying. For David, one summer of fatigue is well worth it.

Long hours of fieldwork mean sometimes missing the spectacular view. Photo: Cassie Gauthier