Descend 55 meters to the floor of Lake Michigan and you’ll find the bottom carpeted with tens of thousands of one of the most prolific invasive species in the Great Lakes: the quagga mussel.

Researchers have long known that these voracious filter feeders impact water quality in the lake, but their influence on water movement had remained largely a mystery.

From 2012 to 2013, Purdue University PhD candidate David Cannon, working under hydrodynamicist Cary Troy, used water velocity sensors to measure dynamics in the deep waters of Lake Michigan near Milwaukee, Wisconsin and determine the filtration effects of the invasive mussels. The project was supported by a grant from the Illinois-Indiana and Wisconsin Sea Grant programs.

Quagga mussels, which arrived in Lake Michigan in the 1990s via ballast water discharged from ships, have colonized vast expanses of the Lake Michigan bottom, reaching densities as high as roughly 35,000 quagga mussels per square meter. The invasive species that can have major economic impacts filters up to 4 liters of water per day, and so far seems unaffected by any means of population control. It is also a constant threat to other systems, as it is readily transported between water bodies.

“Quagga mussels filter by ‘sucking in’ the water around them and then ‘spitting out’ what (nutrients and particles) they don’t want,” said Cannon. “While they’re doing this, they’re able to directly move a very small amount of water around them—only about 10 cm above the lake bed.”

Mussels_Lake_Guardian

Quagga mussels harvested from Lake Michigan.

Although this filtering has a dramatic effect on water quality, the measurements taken near Milwaukee suggest that quaggas do not strongly influence movement throughout the entire water column.

But the movement they cause in the thin layer immediately above the lake bed—a phenomenon consistent throughout the year thanks to stable temperatures at the bottom of Lake Michigan—is an element missing from most mussel filtration models.

Cannon and Troy hope that will now change. Their results could lead to the development of better models to study the effects of these organisms on lakes and reservoirs around the world.

“Although Lake Michigan is already infested with these mussels, an accurate filtration model would be imperative for determining the fate of substances like nutrients and plankton in the water,” Cannon said. “In other quagga mussel-threatened systems, like Lake Mead, this could be used to determine the potential impact of mussels on the lake, which could in turn be used to develop policy and push for funding to keep mussels out of the lakes.”

“It’s generally accepted that the ecosystems of smaller, shallower lakes—Lake Erie, for example—are at the greatest risk of quagga mussel invasion,” he added. “Our results could help show other researchers that the effects of mussels on large, deep lakes cannot be ignored and, more importantly, how they can be accounted for.”

Illinois-Indiana Sea Grant is a part of University of Illinois Extension and Purdue University Extension.

IISG Instagram

📢 Show Your Support for Sea Grant! 📢Continued federal funding for Sea Grant in FY26 is crucial, and we need your help to demonstrate the nationwide support for these essential programs.🖊️ Sign the letter urging Congress to continue funding Illinois-Indiana Sea Grant and all 34 state Sea Grant programs:🔗 https://forms.gle/7sPGHGyh8j8a7vfGA or link in bio
Exciting news! The call for sessions for the 2026 Emerging Contaminants in the Environment Conference has been extended! We are excited to offer the opportunity to propose a speaker or panel session during the 2026 Emerging Contaminants in the Environment Conference April 28-29.  The conference will feature traditional 15-minute presentations and a poster session on the latest in emerging contaminant research, policies, and outreach in the soil, water, and air.The deadline to propose a session is September 30, 2025.Learn more at go.illinois.edu/ecec or the link in bio
Stay safe and have fun this Fourth of July with these 5 water safety tips! Click the link in bio to learn more ways to keep yourself and others safe as you enjoy the Lake Michigan beaches this holiday.
Four science educators from Illinois and Indiana have been selected for the 2025 Shipboard Science Immersion on Lake Michigan July 7-13. The educators will spend a full week alongside researchers aboard the EPA research vessel Lake Guardian. Afterwards, they will bring Great Lakes science back to their classroom. Learn more and meet the four incredible teachers representing Illinois and Indiana at the link in bio.
Skip to content