On Our Dock: High-Water Happenings at Hasler Lab

From broken boards to algal blooms, this summer’s climate has brought new adventures for Hasler Lab’s beloved boat slip. Our summer scicomm intern has the report!

by Madelyn Anderson – The dock at Hasler Lab has seen many things: hungry swallows, roaring waves, scientists sampling. This summer, changing seasons and climate are adding to that list. Cyanobacteria and high water levels have crept onto the boards of Hasler’s dock, seeping into the boat slip and creating new challenges for researchers. 

Last week, Center for Limnology director Jake Vander Zanden spent his day with a tape measure, monitoring the lake which rose just two and a half inches below the surface of the boat slip, threatening to flood the lab’s basement. Outside, dock boards came loose in the waves. Recent (and frequent) rains caused this upwell, threatening to spill over and ensure the wet lab lives up to its name. 

Twenty five sandbags and a hundred held breaths later, our staff let out a sigh of relief as the water stabilized. CFLers spoke about those tense days as historic, saying such high water hadn’t been seen since the big flood in 2018

A group of people fill sandbags..
A team of Hasler Lab staff and students fills sandbags to protect the boat slip from flooding. Photo: Alice Ogden-Nussbaum

But, water isn’t the only element causing chaos on Hasler’s dock. Sunlight on warm summer days has fueled cyanobacteria, or blue-green algae, to photosynthesize and bloom. Caused by excess nutrients in the lake, primarily from agricultural practices in the Lake Mendota watershed, cyanobacteria are a common sight in Madison.

This week, we even spied them on Hasler’s pier. Green splotches coated the ground where water meets concrete, trailing through the boat slip door and into the lab. Researchers scooped up a sample and placed it under the microscope, identifying the bacteria as part of the Gloeotrichia genus. 

Green algae grows on a concrete pier.
The water overtopping the Hasler Lab pier turned into a bluegreen algae Petri dish. Photo: Tyler Butts

Gloeotrichia appear as spheres on surface water, and as puffy fireworks under magnification. They tend to clump in colonies on lakes, and Gloeotrichia echinulata colonies are often found in toxic blooms. While specific cyanobacteria species can be hard to identify, our researchers enjoyed exploring the samples. 

Algae under a microscope.
Gleotrichia (left) look like tiny, puffy fireworks under the microscope. Photo: Tyler Butts

While high water levels and mysterious bacteria can provide excitement at the lab, our researchers are eager to get back to their boats, desks, and labs to investigate lake trends further. What will extreme precipitation and high-water levels mean for our lakes.What if there’s a lack of rain? How will algal blooms continue to spread with warming temperatures? What does this mean for the organisms living in the lake? These are all questions we hope to answer this summer. Well, if we can keep calm on our dock!



Feature photo (above): We had to employ an inflatable dike in our boat slip to keep Lake Mendota from visiting our lab! Photo: Aaron Nolan