The Environmental Protection Agency has been sampling all five Great Lakes for four decades. Every spring and summer crews survey each lake’s water quality.
For over 30 of those years, the mission has been accomplished aboard the Lake Guardian, the EPA’s Great Lakes research vessel.
I met EPA scientists Matt Pawlowski and Megan O’Brien as they were about to set off from Milwaukee’s inner harbor.
O’Brien points to a map on her computer screen.
“So here we are in Milwaukee, and this is our first stop. … We go through there through the Straits of Mackinac, and then down through the St. Clair River, Lake St. Clair and then the next crew gets on,” she explains.
The EPA has been sampling the same locations throughout the basin year after year.
They rely on what O’Brien calls the most standard piece of limnology equipment.
“Our Rosette. Around the outside are these twelve bottles and they each hold about eight liters of water and the unique design is that they snap shut, they open and close simultaneously and so you get a grab of water at that unique depth,” O’Brien says.
The Rosette capture samples at multiple depths at each of the ship’s stops.
“And then on the bottom is our array of sensors — turbidity, connectivity, barometer, temperature, you can see spikes in chlorophyll. … It’s really the heart of what we do,” she says.
As it’s lifted back on board, O’Brien says scientists swarm around the Rosette.
“We have a little table that we set up and it’s kind of like an army of little bees. There’s probably up to eight bottles per jug you have to fill up. So the army of bees comes around filling water, dumping water, rinsing and triple rinsing, and that’s your sample,” O’Brien says.
The Lake Guardian features a labthat allows scientists to start analyzing water samples right away.
“Some of the water samples specifically have a holding time so you have to analyze things within a specific amount of time otherwise various chemical and biological processes will change the nature of the water. If you took it back to the lab, you’d get different data than if you did it right away,” scientist Matt Pawlowski says.
Scientist from partnering institutions work side by side with the EPA team.
"We have cooperators that compete for monitoring cycles. So, the biology program runs on a five-year cycle and Cornell University, Buffalo State and University of Minnesota-Duluth currently are collaborators for this project,” Pawlowski says.
Together the scientists have documented changes in the Great Lakes.
“I think the biggest would be the zebra and quagga mussel invasion about 30 years ago, completely changed the energy in the system. … I think that’s really important to have this long dataset and … we’re one of the only vessels that is capable to work offshore like we do and so the type of data we collect is very non-standard. We collaborate with the states, but a lot of times they’re limited to nearshore areas,” O’Brien adds.
Part of Pawlowski’s job back on land is helping to produce the State of the Great Lakes Report.
“A lot of the data that we collect out on this boat will end up in that report and that is a binational report that we work on with Canada,” Pawlowski says. It’s published every three years with the most recent one published in 2022.
Both scientists say they love working on the Lake Guardian team, despite its challenges.
For starters, they work 12-hour shifts. “You have a little bit of free time, but we’re always operating. That’s a unique ability of this vessel to be offshore so we don’t have to come into port every night, everyone sleeps in bunks, we have showers, laundry, food everything. So when we leave, we don’t get off until Detroit,” O’Brien says.
Both scientists were drawn to the Great Lakes at an early age.
Pawlowski grew up in Chicago. “I grew up loving water and specifically the Great Lakes. And when I went to college, I realized that you could be paid to do science on the Great Lakes. So I thought that sounds like a great deal, I’ll try to do that,” he says.
O’Brien grew up in Milwaukee. During high school, she landed a job with UW-Milwaukee’s School of Freshwater Sciences as a summer technician.
“I’d always look at the big ship, the Lake Guardian. I always thought I really want to work on there when I’m an adult. … I always wanted to be a part of it, since I was in high school,” O’Brien recalls.
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