Researchers and student scientists look to Missouri lakes for clues about the impact of climate change
Sitting in the middle of Cosmo-Bethel park across from Rock Bridge High School, Bethel Lake hosts an entire ecosystem that could hold clues about the future of climate change in mid-Missouri. That’s what brought Gregory Kirchhofer’s environmental science class out to the park on a warm fall day.
The high school students collected lake water with a basket and recorded the water and air temperature. Ethan Chen leaned forward at the water’s edge and swirled the basket around in the shallows.
“We put the water basket deeper into the pond because it gets more algae that way,” Chen explained.
This sampling was part of a project with the Lakes of Missouri Volunteer Program to predict the effects of climate change on midwestern reservoirs. These water samples will be tested for nutrients like nitrogen, phosphorus, and chlorophyll, which serve as indicators of potentially harmful algal blooms.
With the water collected, the class headed back inside to analyze the samples they’d gathered. They unpacked their gear, and Blake Molesky took the lead in testing the water they collected.
"Some of the samples get sent to the lab some filtered some not to get tested for certain things," Molesky said. "Phytoplankton, fish pee and stuff like that”
Other water samples are run through a vacuum pump to measure amounts of sediment and algae in the water. Molesky said they appreciate being able to learn scientific projects with a hands-on approach.
“It’s interesting to see how things that we do affect the environment.”
The Rock Bridge students are part of Reservoir Observer Student Scientists, a subset of the Lakes of Missouri Volunteer Program.
Jacob Moore is a first-year M-U graduate student in the College of Agriculture, Food and Natural Resources. He oversees communication and delivers presentations for these high school students, as well as preparing any supplies they need.
"It is an attempt to anticipate the effects of climate change before they happen, although they are already occurring," Moore said. "So the winter season is shortening ice cover is growing thinner. It's also on the lake for less periods of time, and some of these lakes start to lose their ice cover due to climate change."
The nutrients the students look for serve as indicators for potentially harmful algal blooms. Those blooms are more prominent in less oxygenated waters, which are in turn caused by increasing air and water temperatures. The blooms can be harmful because they can suck up oxygen in the water, creating dead-zones where there isn’t enough oxygen left to support typical aquatic life.
For Moore, the program is important because it exposes high school students to environmental fieldwork.
"At that age, it's something I would have been really excited about having the opportunity to do," Moore said. "At the end of the day, what they do is almost identical to what I do every week out at Stephens Lake, which is part of my master's project."
With winter weather bearing down, ice could soon start covering Bethel Lake. But the thickness of that ice cover may be less than in previous decades, as climate change continues to shorten the lake’s winter season.
How the data the students collect is used
Dr. Rebecca North is an assistant professor of water quality at MU’s College of Agriculture, Food, and Natural Resources. Her research focuses on reservoirs and lakes. Specifically, how decreasing oxygen concentrations and changes in nutrient availability can affect a lake’s ecosystem. One of the things North looks at are how different layers in bodies of water interact.
"If you've ever been swimming, and you'll notice that you know your feet are colder than the top of your body, this is because something called a thermocline sets up in lakes.”
Basically, the thermocline is where warmer waters at the surface — which get more light — and colder, deeper waters meet. While the top waters get oxygen from interacting with the atmosphere, the bottom waters are cut off. And decomposition, which happens in those bottom layers, in turn lowers oxygen levels. That is bad news for aquatic life.
"So you know, certainly if you have no ability to move, like, if you're [a] macroinvertebrate, or some kind of mussel or clam, or something, it's likely you're going to die," North said.
According to North, increasing air temperatures, which are becoming more common with climate change, warm the water’s temperature, causing stratification: the separation of water into distinct layers by temperature. And so oxygen concentrations vary depending on the area of the lake.
For her research, North uses samples taken as part of the Lakes of Missouri Volunteer Program, a collaboration with the Missouri Department of Health and Senior Services.
The project relies on thousands of samples from 115 sites at 64 lakes, collected by volunteers like the Rock Bridge students who sample Bethel lake as part of the Reservoir Observer Student Scientists program. Tony Thorpe is involved in both of these programs.
"Our goals are to understand what current water quality conditions are throughout Missouri's lakes, to monitor for those changes in those conditions over time, and then also to interact with and educate Missouri residents about water quality and nutrient impairment and the problems they can cause," Thorpe said.
Thorpe is the coordinator for the Lakes of Missouri Volunteer Program. He works with volunteers and reports data to the Missouri Department of Natural Resources, which funds the project.
"It's a great way for people to get out and get involved in science.”
Since the volunteer program started in 1992, it has recorded key water quality metrics like temperature, water clarity, and nutrients in lakes across the state.
Even before the volunteer program began state officials kept a record of water quality samples for more than a decade. When they started in 1978, climate change was far from the pre-eminent concern it is today.
But North realized that long-term data would still be useful in comparing Missouri reservoirs to those around the world.
"There’s not very many places in the world where you have 40 years of consistent sampling to be able to look for these long term trends," North said. "And so instead of ... working on things in your own backyard and coming to conclusions, you often ask, well, is this is this happening other places?”
Around the world, as water temperatures warm, stratification starts sooner and sooner in the year due to climate change.
"Part of the study were 50 reservoirs here in Missouri, but also lakes in Africa, and Europe and Canada, and ... all over the world,” North explained.
The Rock Bridge students are likely to see the bulk of climate change impacts in their own lifetimes, so researchers, including North, believe it’s important to get them involved in learning from their environment early on.
“It looks quantitatively like they've learned a lot by participating in the program. Their data that they collected and they processed is going in the scientific literature.”
And their work will become part of a data set 30 years in the making, helping with research that will only become more valuable over the course of their lives.