By Andy McGlashen
In a nod to a Saturday Night Live sketch, environmentalists in 2010 dubbed the Bay Shore power plant near Toledo the “Bass-o-Matic.” They said it killed about 60 million fish each year as it sucked in water for cooling.
Critics also said the plant helped harmful algae grow by dumping heated water into Lake Erie’s Maumee Bay.
And plant operator FirstEnergy shut down most of the coal-burning facility last year because it polluted more than tightening federal rules allow, and the upgrades to bring it into compliance were expensive.
But the Bay Shore plant has a greener side.
A study in the Journal of Great Lakes Research shows native mussels thrived within the plume of warm water the plant discharged. It was a refuge from a raging ecological storm that threatens to wipe native mussels out of the Great Lakes altogether.
While it’s good to locate a healthy population of native mussels, the findings are a sad commentary on the state of the Great Lakes, said study co-author Todd Crail, a lecturer in environmental sciences at the University of Toledo.
“At face value it might seem like a positive thing, but I think it really speaks to the point of how abysmal the overall situation is, if that is the one place where you have conditions that are left for these organisms to survive,” Crail said.
Native Great Lakes mussels have been on the ropes for decades. They are especially sensitive to water quality. Heavy metals, farm runoff and other pollutants contribute to their decline.
Meanwhile, dams, dredging, shipping canals and other engineering projects have stripped away mussel habitat by altering the sediment of lake and river bottoms where they burrow for shelter. Some river-dwelling species have been buried in silt while parts of the lakes are starved of sediment, leaving mussels unable to burrow into hard clay, Crail said.
But the biggest hit–and what still could prove to be the knockout punch–came in the 1980s when invasive zebra and quagga mussels arrived. They cling to the shells of native mussels, making it difficult or impossible for them to eat or breathe. The invasives have since wiped out more than 99 percent of native mussels from the open waters of Lake Erie and Lake St. Clair, according to the Environmental Protection Agency.
Pockets of protection
The Great Lakes’ remaining native mussels are hanging on in a handful of river deltas, sheltered bays and other isolated coastal pockets. One such refuge is where the Bay Shore plant discharges its warm water–a cove sheltered by an island of dredged sediment–according to Crail and colleagues.
The researchers found more native mussels, bigger individuals and a greater diversity of species within the warm water plume than outside it. They also found fewer invasive mussels clinging to native species in the warmer discharge area.
Crail said he was surprised when the team found that mussels near the power plant had more sediment for burrowing–sediment made of the shells of dead zebra mussels, quagga mussels and Asian clams, another invader.
“There are so many of them that it’s starting to build sediment in the lake again, which is crazy,” Crail said. “We’re fixing problems with problems, so that’s not really a fix.”
It’s anybody’s guess at this point whether the Bay Shore plant will continue to harbor a healthy mussel population now that it’s mostly shuttered, he added.
Mussels aren’t the most compelling poster children for environmental protection. Why should anyone care about faceless, immobile mollusks with names like white heelsplitter and Wabash pigtoe?
Saving native mussels is really about protecting entire Great Lakes ecosystems, said David Zanatta, associate professor at Central Michigan University’s Institute for Great Lakes Research.
“If they’re showing a decline in diversity and abundance, it’s a clear sign that other species are under threat,” said Zanatta, who was not involved in the study.
He said there is hope for restoring Great Lakes mussels. For instance, pollution controls and other measures have restored habitat in many streams, but populations there are cut off from others of their species.
“What caused their declines might no longer be present, so we could start to artificially propagate some of these populations,” Zanatta said.
Another possible measure is constructing barrier islands out of dredged sediment, like the one near the Bay Shore plant, to provide pockets of habitat, Crail said. But people typically don’t like such drastic changes.
“If I were king and I didn’t have to listen to anybody else, that’s what I’d do,” he said. “But I imagine there would be a lot of fight back against that. ”
More fundamentally, Crail said protecting mussels and other species means preserving natural shorelines. About 20 percent of Lake Erie’s shoreline is mostly or entirely hardened with seawalls and other structures that alter the natural flow of sediment, according to the EPA.
“Maybe we need to rethink what our shoreline looks like,” he said. “We tend to be like, ‘This is lake, this is not lake.’ And nature tends to function best when it’s a gradient of conditions.”
That’s the idea behind The Nature Conservancy’s project to restore its 2,200-acre Erie Marsh Preserve. The marsh, in North Maumee Bay, includes 11 percent of Southeast Michigan’s remaining coastal wetlands.
“It’s all native marsh. There’s no concrete or riprap,” said Chris May, the group’s restoration manager for Michigan.
There are, however, dikes to stabilize the marsh and allow managers to create a variety of habitat types. Built in the 1940s, the structures also cut it off from Lake Erie.
One component of the project–funded by a $2.6 million Great Lakes Restoration Initiative grant and expected to wrap up by 2017–involves installing structures to allow fish and other species to move between the marsh and Lake Erie. Since native mussels rely on fish to spread their larvae, May said the improvements could help boost mussel populations in the marsh.