Not all alien species are from deep space, and not all alien invasions raise a ruckus. Of particular interest to scientists at the Smithsonian Environmental Research Center (SERC), on the Chesapeake Bay in Maryland, are aliens who arrive stealthily: marine organisms that enter environments to which they’re not indigenous and cause ecological and economic ruin. The use of the word "invasions," borrowed from warfare, suggests how much is at stake. The annual loss to the U.S. economy caused by these intruders—through damage done to fisheries, for example—has been estimated at $137 billion.
How do foreign aquatic species get to the Chesapeake? The ballast water released by ships traveling between distant ports is one way, and SERC has become a clearinghouse of information about "ballast-mediated invasions." Its scientists have compiled a database of more than 600 invasive species along U.S. coasts, of which about 160—including the European green crab, the Chinese mystery snail, Asiatic clams and various families of tube worms—are found in the Chesapeake Bay. The bay has undergone an environmental transformation, and not for the better.
SERC (pronounced like the circ- of circle) is ideally situated on 2,800 acres of forest, cropland, pasture, freshwater wetlands, tidal marshes, and estuaries along the shore of the Chesapeake, and those alien marine species are but one of its concerns. In fact, SERC is now the world’s leading center for the comprehensive study of coastal zones, where varied ecosystems interact with one another and are affected by linkages between their aquatic, terrestrial and atmospheric components. The mission of the researchers at SERC is to make sense of these complex settings where land and sea meet. Their work has a special urgency because fully 70 percent of the world’s growing population now inhabits coastal zones, and most of the world’s environmental challenges are being played out amid the zones’ ecosystems.
The Smithsonian is fortunate to own all the acres that are SERC’s natural laboratory. Nowhere else do researchers have such unfettered opportunity to explore, at a permanent research site, the interaction of linked ecosystems. SERC’s research is patient and extensive, reflecting more than three decades of environmental change in the nation’s largest estuary. What SERC scientists learn bears on environmental issues around the globe, so they extend their studies through a far-flung network of comparative field research sites and collaborators. The knowledge gained locally mounts an invasion of its own, entirely beneficial, and makes its way across the world’s latitudes.
The species with the greatest sustained commercial catch in the Chesapeake is the blue crab, long a symbol of the bay and a source of livelihood for many inhabitants of the region. But even blue crab stock has declined by more than 80 percent in the past dozen years. SERC scientists have amassed decades of information about the crabs, in part by fitting hundreds of the species with biotelemetry devices to monitor their behavior. Burdened by wires and tape, the crabs seem unlikely research recruits. The data they send back from the deep may, in time, allow our scientists to devise solutions that preserve blue crab fishery in the bay. And in the survival of one species, there may be hope for others. Through their meticulous study of the intricate life along the Chesapeake, SERC scientists are helping to sustain coastal ecosystems around the world.