PSU Magazine Winter 2004

Species picked up accidentally from ships abroad post real threats to North American ecosystems. In 1988, residents of Lake St. Clair, part of the Great Lakes system, spotted a tiny, attractively striped shellfish. The diminutive zebra mussel was strikingly beautiful and , it turned out, stagger– ingly dangerous. Two years later, the non-native transplant from Europe had infiltrated all of the Great Lakes. Five years after first being discovered , the zebra mussel was abundant as far south as the Gulf of Mexico. And throughout their new territory, the beautiful invaders wreaked havoc-clogging municipal water sup– ply pipes and choking cooling water intakes on nuclear reactors. Even more disquieting, the minis– cule invaders have dramatically altered the ecosystem. Zebra mussels are more effective at filtering water than native bivalves are. ln some areas, zebras have sucked out as much as 80 percent of Lake Erie's phytoplankton, algae, and zooplank– ton. The lake appears cleaner-but by removing the basic food source, the mussels are starving native fauna further up the food chain. And the tiny mussels absorb far more contaminants than native mol– lusks do, which in turn increases the speed at which those toxins shoot up the food chain when fowl and fish feast on the zebras. G overnments in the Great Lakes region spend millions of dollars each year to unclog intake pipes and prevent further infestation. In all, more than $1 billion has been spent attempting to remove the tenacious aliens. Results have been disheartening. Today the zebra mussel infests more than 40 percent of U .5. inland waterways. WINTER 2004 PSU MAGAZINE 9