A collaborative research project about the impacts of quagga mussels in Lake Michigan has led to more funding for the issue from the National Science Foundation (NSF). The original project, jointly supported by the Illinois-Indiana and Wisconsin Sea Grant programs, looked at the effects of this invasive mussel in the deep parts of Lake Michigan on plankton abundance, the phosphorus cycle, and water movement.

Harvey Bootsma

The new project is funded by the Biological Oceanography and Physical Oceanography divisions of NSF for more than $1 million with the expectation that the results will be useful in understanding conditions in other large lakes as well coastal areas.

The principal investigators are Harvey Bootsma and Qian Liao with the University of Wisconsin-Milwaukee,

and Cary Troy with Purdue University. David Cannon is a Ph.D. student working on the project at Purdue.

In the original project, the team discovered that quagga mussels in Lake Michigan are eating more plankton than what is reaching them by sinking from above. They’ll be looking at how and why this could happen with the new project.

“We think that food delivery to the bottom of the lake is not just determined by the passive settling of phytoplankton as it’s sinking through the water, but that

Cary Troy

plankton is always being circulated in the lake,” said Bootsma. “It’s like the plankton are on a kind of conveyor belt where they’re going up and down.”

The researchers now will be studying turbulence in the entire water column.

Troy studied the impact mussels have on water movement as they filter it—sucking in water and spitting it

out. “Although this filtering has a dramatic effect on water quality, we found that quaggas do not strongly influence movement throughout the entire water column,” explained Cannon.

But the movement they cause in the thin layer immediately above the lake bed—a

Qian Liao

phenomenon consistent throughout the year thanks to stable temperatures at the bottom of Lake Michigan—is an element missing from most mussel filtration models.

The researchers also found that the mussels are changing the phosphorus cycle in the lake. “The nutrient-loading models used to set limits for phosphorus aren’t accurate anymore because of these new components to the ecosystem – bottom-dwelling filter feeders,” Bootsma said. “They have changed the rules for how Lake Michigan works.

David Cannon

“Lake managers have a conundrum right now. They’ve got too much algae in the nearshore zone and they want to reduce phosphorus to solve that problem. But there’s not enough phytoplankton in the offshore zone because of the mussels. So if they reduce phosphorus loading in the lake, they could make that offshore problem even worse so that there’s virtually no food left out there for the rest of the food web,” Bootsma said.

With the new project, Bootsma said his team hopes to determine what the “sweet spot” is for phosphorus loading. “There may not be one perfect phosphorus load that solves both the nearshore and offshore problem, but we’d like to try and find one that minimizes the nuisance algae while at the same time keeps the offshore animals alive with enough plankton production.”

The NSF project will start this spring. “Although we’re focusing on Lake Michigan, the work has implications for most of the other Great Lakes as well as other lakes in general that are being invaded by mussels,” Bootsma said. “We’re looking at a fundamental change in the way lakes work, and that’s the kind of thing the NSF is interested in.”

“It’s generally accepted that the ecosystems of smaller, shallower lakes—Lake Erie, for example—are at the greatest risk of quagga mussel invasion,” Cannon 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.”

Irene Miles, IISG coordinator of strategic communication, contributed to this post.

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

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.”

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.

INVASIVE SPECIES EDITION—Where we take a moment to explore the species that potentially threaten the Great Lakes region.

Zebra and quagga mussels have already made homes in the Great Lakes region, but there’s another invasive clam on the horizon we should keep our sights on. While still limited to countries in South America, researchers predict that the golden mussel could colonize areas in North America where zebra and quagga mussels could not, devastating what native clam populations remain.
 

As with most invasive species, the success of the golden mussel is rooted in its versatility. A freshwater clam, it can survive in higher temperatures, lower pH levels, and higher salinity than either zebra or quagga mussels. Although no effective method of control has been established, research is being conducted on the potential for sterilization via genetic modification.

Even before zebra and quagga mussels arrived in the Great Lakes in the 1980s, the future looked a little bleak for native mussels. The invaders came close to wiping them out entirely. But small populations in Lake Erie appear to not only be surviving the invasion, but thriving. 

Average density of native mussels before the arrival of zebra mussels was two per square meter in Lake St. Clair. By 1990, zebra mussel density was at 1,600 per square meter. 

“By 1992, native mussel populations are almost gone from the southeastern portion of the lake and declining rapidly in the northwestern portion of the lake,” said [Dave] Zanatta, [a biologist at Central Michigan University]. 

By 1994, there were almost no native mussels left in the lake, with zebra now at 3,000+ per square meter. 

“But there was reason for hope,” said Zanatta. “Remnant populations of native mussels were beginning to be found in coastal wetlands in western Lake Erie in the late 1990s.” 

Zanatta’s research adds further evidence that progress continues to be made on one of the impairments of the St. Clair River – the degradation of fish and wildlife habitat – that led to its classification as an environmental Area of Concern in 1985. 

His work also sheds light on the complex ecological impacts of invasive species generally. 

With some environmental observers predicting a doomsday scenario for native game fish if Asian carp are able to establish themselves in the Great Lakes, for example, Zanatta’s mussel research suggests that the outlook for native fish might be significantly more positive than forecasts suggest.

To read the full article, click on the link above. 

**Photo of zebra mussels courtesy of Michigan Sea Grant. 

“Now the mussels may have met their match: Daniel P. Molloy, an emeritus biologist at the New York State Museum in Albany and a self-described ‘Bronx boy who became fascinated by things living in water.’

 

Inspired by Rachel Carson’s ‘Silent Spring’ in high school, Dr. Molloy, now 66, has long been a pioneer in the development of environmentally safe control agents to replace broad-spectrum chemical pesticides. 

 

Leading a team at the museum’s Cambridge Field Research Laboratory in upstate New York, he discovered a bacterium, Pseudomonas fluorescens strain CL145A, that kills the mussels but appears to have little or no effect on other organisms. 

 

As a result, New York State has awarded a license to Marrone Bio Innovations, a company in Davis, Calif., to develop a commercial formulation of the bacterium. The product, Zequanox, has been undergoing tests for several years, with promising results. (Dr. Molloy has no financial ties to the company.)

 

Zequanox killed more than 90 percent of the mussels in a test using tanks of water from Lake Carlos in Minnesota, said James A. Luoma, a research biologist with the United States Geological Survey in La Crosse, Wis. A control group of freshwater mussels, unionids from the Black River in Wisconsin, were unharmed.”

Quagga and Zebra Mussels are well-known names in the Great Lakes region, as these invasive species have already had an effect on marine wildlife. But both species are prevalent in waterways throughout the United States, and fighting their spread could require a boost from the Federal government. 

From USA Today: 

“The mussels, natives of Eastern Europe and Western Asia, were transported to the U.S. in the ballast water of trans-Atlantic cargo ships. They first appeared in the Great Lakes in the mid-1980s, and between 2000 and 2010, they cost that region’s water users some $5 billion. The invaders have since crossed the Rocky Mountains, likely hitching a ride on a vacationer’s boat (they can survive for weeks out of water).

 

Their rapid spread threatens water supplies and energy systems in the West, a region heavily dependent upon hydropower and often gripped by drought. In response, state officials have stepped up boat inspections and cleaning efforts in addition to calling for federal help.”

The folks at Wildlife Forever have teamed up with several partners including the North American Fishing Club to produce a series of television programs about aquatic invasive species that are threatening our waters. 

Episode three of “Silent Invaders” offers an up-close and informative look at Asian carp, just one of several species that has either taken hold in our waterways or is threatening to spread and cause significant changes to important ecosystems. 

You can watch the entire episode online here, as well as episodes providing information about Zebra and Quagga mussels and round Gobies.