Researchers have a new way to study Lake Erie thanks to a Stone Laboratory facility that is the first of its kind on the Great Lakes.

Stone Lab’s Mesocosm Facility, which opened in 2022, bridges the gap between small-scale laboratory studies and broader environmental research.

The open-air facility, located next to the Aquatic Visitors Center on South Bass Island, contains 15 circular, 600-gallon tanks, called “mesocosms,” that researchers are using to study organisms ranging from algae and bacteria to adult fish. The tanks can pump in water from Lake Erie to replicate the natural environment on a larger scale than what’s possible with “microcosms” like beakers, bottles or fish tanks.

“It allows us to do research that wasn’t possible before,” said Justin Chaffin, research coordinator at Stone Lab. “We’ve been doing small-scale experiments for years, but we can’t do controlled experiments out in the lake. So the Mesocosm Facility allows us to do research at a larger scale that can be better extrapolated to the natural system.”

The facility came about thanks to $2.65 million in state funding that Stone Lab received in 2019 to increase laboratory space. Stone Lab researchers highly requested a new facility for experiments, Chaffin said.

“If we all do the same experiments across the Great Lakes in the same kind of facility, we should have larger scale implications for our results.”
Justin Chaffin

“Mesocosms help eliminate artificial results that pop up in small-scale bottle experiments,” Chaffin said. “And then we can also do experiments with adult fish. You can’t put a 30-inch walleye in a fish tank, but we can put many in a mesocosm tank.”

To create the Mesocosm Facility, Stone Lab consulted with engineers at the Woods Hole Oceanographic Institution, which houses a similar station in Massachusetts. Stone Lab’s 1,500-square-foot facility was designed to function outdoors, making it the first open-air mesocosm facility on the Great Lakes.

“It’s more exposed to the elements,” Chaffin said. “You get the natural sunlight, cloud cover, rain, wind. Everything that’s happening in the lake can influence what’s happening in the mesocosm when it’s an outdoor facility.”

The facility’s tanks offer researchers flexibility. The mesocosms can function with water flowing to and from Lake Erie, or they can serve as batch culture-like experiments. Filters are available to remove particles down to the size of a micron — one-millionth of a meter.

“So however the researcher designs their experiment, with raw or filtered water, we could do either,” Chaffin said.

Overhead support structures can hang shade cloths to reduce light intensity or hang scientific instruments in the center of the tanks. Each tank has forced air to provide organisms with oxygen and 120-volt electricity for easy access to instruments needing power.

Another essential feature: round tanks.

“We knew right from the beginning we wanted round tanks because we were going to do experiments with fish, and fish don’t like corners,” Chaffin said. “They bump their head into the wall.”

This summer, scientists are using the facility to study how smallmouth bass will respond to a changing climate and to determine the impact federally registered algaecides have on zooplankton, small shrimp-like creatures that are important food for fish.

Chaffin anticipates researcher demand for the facility will keep growing, and he hopes to keep growing the facility itself. One goal is to equip the tanks with improved, automated instruments that monitor temperature and dissolved oxygen and report data every couple minutes. A broader goal is to create similar outdoor facilities at other field stations around the Great Lakes.

“If we all do the same experiments across the Great Lakes in the same kind of facility, we should have larger scale implications for our results,” Chaffin said.