NEWS & PUBLICATIONS

National parks within the fragile Great Lakes ecosystem face serious environmental threats. But there’s still hope for this vital resource, which provides recreation and sustenance to millions.

Ryan Koepke has fished Lake Michigan for most of his life. He first dropped bait and hook into the Great Lake with his dad at the tender age of two.

Today, he and his brother regularly take their young kids out fishing. "You get out there and it takes your breath away," he says of the vast beauty. He hopes his five-year-old daughter, Alexandria, will get to experience the same joy he did growing up as a child on the shores of Lake Michigan. But Koepke, who works in the visitor information center at Indiana Dunes National Lakeshore, is not certain that she’ll always have that opportunity.

Now, the Great Lakes and the parks within the Great Lakes Basin face a combination of threats—from occasional sewage system overflows, to mercury contamination, to invasive exotic species, and more. These disturbances are harming ecosystems that have already suffered heavy blows. In the words of some scientists, we may be near a "tipping point" with the Great Lakes, in which a combination of ecological disturbances could send the natural system out of balance. Koepke hopes that won’t be the case. But to head off such irreversible damage, he and other observers agree, will take concerted effort.

This is not the first time the Great Lakes have faced serious threats. In the early 1900s steel mills, oil refineries, and chemical plants discharged enormous quantities of waste into these waters. One historian wrote that skies near Chicago and Gary, Indiana, "glowed red at night from iron oxide particles spewed by open-hearth ovens. Slag from blast furnaces was used to fill swampy land and extend the lakeshore, while coal tars from coke plants and acids from finishing mills coated the Grand Calumet River."

At the same time, overfishing caused precipitous declines in fishery harvests. Intensive logging on the shorelines and along rivers and streams poured mountains of sediment and debris into the lakes. Raw sewage sometimes found its way into the lakes, because of poor or nonexistent water treatment systems.

Today, the dangers facing the Great Lakes are less obvious, but perhaps no less threatening. Although industrial and sanitary wastes, fishing, and logging are more closely monitored and managed today thanks to legislation passed in the 1970s, the Great Lakes are still under duress. The 18 national park units within and around the Great Lakes face these same threats, to varying degrees, on the basis of their location within the Great Lakes Basin.

Along the southern shores of the Great Lakes, less than an hour’s drive from downtown Chicago, lies Indiana Dunes National Lakeshore—15,000 acres of dunes, wetlands, woodlands, and beaches stretching along 25 miles of Lake Michigan's shoreline. Last year, more than 2 million people visited the park—more than visited Glacier National Park in Montana—but sadly, day-trippers and out-of-town tourists can’t always swim at the sandy beaches or eat the fish they catch from the shore.

"Our sewer systems are old," explains Wendy Smith, an educator at the Great Lakes Research and Education Center at Indiana Dunes. When heavy rain comes, the sewers "can’t accommodate all the storm water, so some of the mix goes straight into the waterways without being treated." That sometimes means park authorities must post signs advising visitors not to swim in Lake Michigan. Anglers, too, must exercise caution before putting the day’s catch on a dinner plate. Visitors are advised not to eat large fish. "There are a lot of fish in this region that you don’t eat, period, because of the accumulation of toxic contaminants," reports Smith. Many fish species harbor unsafe levels of PCBs—a leftover from industries decades ago.

Fortunately, sewage and industrial waste are better controlled today, and beach closings are less frequent. Meanwhile another dire threat has emerged: the introduction of alien fish, animal, and plant species. Researchers say at least 170 aquatic invasive species currently live in the Great Lakes Basin—and a new species is introduced on average once every eight months.

Lake Michigan has already been hit hard by invasives, according to Koepke, who warns that if the next looming threat—Asian carp, already discovered in the nearby Mississippi and Illinois Rivers—gets into the Great Lakes, it could portend the end of the fishery altogether. Like an underwater vacuum cleaner, the Asian carp can filter up to 18 liters of water per hour, removing vital life-giving plankton from the lakes every minute.

Other invasive species that have caused severe ecological disturbance include the fecund and ravenous zebra mussel, the adaptable and voracious round goby, and the parasitic, blood-sucking sea lamprey. These and other invaders alter the food chain and contribute to sharp declines of lake perch, lake trout, and other fish. "Twenty-five years ago you could go out there and catch an entire bucket of perch," recalls Koepke. Not today.

As zebra mussels filter lake water, water clarity increases and aquatic plants grow in number and size, causing problems for recreational boaters and swimmers, and even blocking water-intake pipes during storm events. Meanwhile invasive plant species threaten to out-compete rare and endangered native species. Such is the case in the northwest corner of the Great Lakes Basin, where Apostle Islands National Lakeshore—an archipelago of 21 emerald islands surrounded by the cold, deep waters of Lake Superior—faces green invaders.

The rugged, rocky shores here harbor old-growth forests, sandstone bluffs, sea caves, more than 100 bird species, 800 plant species, and 35 mammal species. But native plant species are threatened by invasives such as hawkweed and spotted knapweed—an invader that could "raise havoc" in the park’s sandy areas, according to Julie Van Stappen, a natural resources expert at Apostle Islands National Lakeshore.

At the Apostle Islands, ecologists have attempted to restore the native vegetation by propagating native plants and planting them in denuded or trampled areas. It’s an effective strategy but it’s time-consuming and expensive—a difficult combination in an era of tighter and tighter budgets. "Our staff is getting cut," reports Van Stappen, and without staff, she says, she won’t be able to monitor the natural systems as well as she would like.

Yet another threat to this pristine park comes from above. The skies over Lake Superior drop contaminants such as mercury into these waters. Mercury, explains Van Stappen, forms from power plant combustion and the burning of waste. Like many toxic substances, mercury becomes more concentrated as it moves up the food chain, a process called bioaccumulation.

Van Stappen says the park's inland lagoons have "extremely high" levels of mercury. Not surprisingly, park researchers testing blood samples from eagles and hair samples from otters have found high levels of mercury. Fish and other animals can take in mercury through direct contact from their environment and by consuming organisms that are already contaminated with the substance. The higher a creature is on the food chain, the greater the impact, whether that creature catches its prey with claws, talons, or a rod and reel.

This combination of threats confronts an ecosystem that has already suffered heavy blows, some of which have affected the lakes for nearly a century, such as overfishing, urban and agricultural runoff, and toxic dumping.

In the past, the lakes had a better ability to cope with these disturbances. But the continued effects of these events combined with the loss of wetlands, the degradation of shorelines, and invasive species, have caused the Great Lakes to lose much of their ability to handle environmental stress.

It may not be long before water becomes a global priority and Americans begin to appreciate the value of the largest fresh-water system in the world So researchers are calling on policymakers to improve shorelines and wetlands; limit existing sources of pollution; halt new exotic species from entering the lakes; and protect less-developed areas by adopting sustainable land-use practices.

Legislation passed by the U.S. Senate in July would devote $20 million to grant programs to restore fish and wildlife in the Great Lakes, reauthorizing legislation originally enacted in 1990 and then again in 1998. Sixty-five projects have been funded since then, focusing on habitat restoration, habitat assessments, and the impact of non-native species.

"We’ve inherited a lot of problems from the previous generation," says Cameron Davis, executive director of the Alliance for the Great Lakes. "We owe it to the next generation not to hand those down and, in fact, to correct some of those problems today. The Great Lakes may face irreversible damage unless we act now."

Brian Lavendel is an environmental writer who lives in Madison, Wisconsin.