Scientists from Bowling Green State University recently joined researchers from across the region to study the persistence of algal blooms in the Great Lakes during the winter months.
George Bullerjahn and Mike McKay of BGSU’s Department of Biological Sciences were part of a collaborative effort called “Winter Grab,” an effort to sample the five Great Lakes during the winter to better understand how they function during a period of the year. when little is known about them.
Although spring is often touted as a time of rebirth, scientists have observed that the winter months on the lakes are also active. The Great Lakes have been studied extensively before, but nearly all of what researchers know today comes from the warmer months, when little was known about how they function during the winter.
“We defined it as a kind of ‘black box’ for our understanding of how the Great Lakes work,” McKay said. “There are three months of the year when we have virtually no information, whether it’s because of the logistical challenges of sampling in the winter, access to safe sampling platforms, or simply the notion that nothing happens in the winter, it’s too cold and things go to sleep. We know that’s not the case.
The project includes dozens of scientists from many different universities and disciplines who study lakes to gain a more complete understanding of their ecosystem. Professor Ted Ozersky of the University of Minnesota-Duluth proposed the study, which will be contributed by researchers from BGSU, Ohio State, Michigan, Wright State, Oberlin, Lake Superior State, Central Michigan, Clarkson, and the University of Chicago.
The Cooperative Great Lakes Research Institute funded the study, which also includes government agencies such as NOAA’s Great Lakes Environmental Research Laboratory and three Canadian universities.
Bullerjahn, McKay and BGSU graduate student Ryan Wagner visited Sandusky Bay to measure light extinction – the amount of sunlight that passes through the ice – as well as collect samples for plankton identification, chemical and physiological measurements as well as genomics.
Bullerjahn and McKay have studied the Great Lakes for many years and observed the two high ice years like 2014 and 2015, but saw the opposite in 2022 when there was very little ice. Due to climate change, the lakes have seen a 71% decline in ice cover over the past 50 years, making years like this more frequent on average.
Studying lakes during low-ice years, in particular, could provide a window into how they will behave as they warm.
“We studied high ice years and low ice years and showed that there are differences in algal composition between high ice years and low ice years,” Bullerjahn said. “It gives you insight into how lakes may change over time due to climate change.”
The BGSU lab portion of the study will focus on winter photosynthesis. They examine how the lower food web behaves during the winter months, how winter algae may contribute to summer hypoxia – low oxygen dead zones – in the central basin of Lake Erie, and what winter photosynthesis means. for lake life such as fish.
Although the cold can inhibit some life forms, BGSU researchers have observed that lakes are more active in winter than previously thought.
“Even though winter may seem extreme, there are life forms that will not only live or persist, but will thrive,” McKay said.
Through collaboration between many different entities, the teams seek to establish a baseline that yields a deeper understanding of the chemistry and biology that sustain all life forms.
“That’s what the Great Lakes Winter Survey is all about – to really look at what’s going on and establish a baseline,” Bullerjahn said. “Then hopefully in subsequent years we can do a lake-to-lake and year-to-year comparison study.”