Striving to keep aquatic invaders at bay

Edgewater facility home to Smithsonian scientists

January 26, 2003|By Kathy Bergen Smith | Kathy Bergen Smith,SPECIAL TO THE SUN

Tim Mullady peers into a microscope in a darkened room at the Smithsonian Environmental Research Center in Edgewater. He is counting cells from a sample of ballast water taken from a ship, looking for vibrio cholerae, the bacterium that causes human cholera - and sometimes is discharged from that ballast into local waters along with scores of other "foreign" organisms.

Mullady is part of the National Marine Invasion Research Program, which provides the Coast Guard and Congress with information from the forefront of the research community on this issue.

Run by Greg Ruiz, the lab is the largest research program in the country focused on what scientists call "introduced marine species," everything from bacteria to zebra mussels.

The researchers study the biology underlying invasions, including especially the introduction of ballast water and all the "hitchhikers" it brings with it, as well as ways to treat the ballast water to minimize its effects.

"While our mission is to do high quality research here, our work has relevance to issues that are important for resource managers and policy-makers," Ruiz said.

The lab's work has renewed urgency because of the Coast Guard's recent rule imposing stiff penalties on ships that fail to provide information about their ballast water. Although currently required, reporting rates are low, prompting new fines for ships that do not report.

Ballast is weight added to a ship to keep it stable. A cargo ship carries ballast in the form of water, often millions of gallons, when it is not loaded. Before a ship leaves port, its ballast tanks are flooded by pumping water, and everything else that comes along with it, through pipes that are 3 inches in diameter.

Because harbor water teems with life, ballast water carries everything from bacteria and other microscopic organisms to fish and crabs.

`A history of invasion'

The ship's ballast tank is like a giant aquarium, repeatedly filled and discharged at ports throughout the world, releasing a rich mixture of organisms in the process.

Until zebra mussels, native to Eurasia, began clogging the water intake lines of the cities along the shores of the Great Lakes, few thought much about the ecological effect of dumping ballast water. Since then, the scientific community has sought to assess the breadth and scope of species introduced into coastal waters via the discharging of ballast water.

"We found that Chesapeake Bay, in particular, has a history of invasion," says Ruiz. The devastating oyster disease MSX, for example, was identified as an introduced species.

The "Invasion Lab" headquarters is in a modern lab facility on the SERC campus. In one room, what appear to be large refrigerators line the walls. Ruiz explains that these incubators simulate different environmental conditions. Here researchers can evaluate the tolerance of introduced species to different temperatures and other conditions.

The main lab is a beehive of activity as staffers pursue different research projects. The staff of 30 is composed of visiting researchers, doctoral candidates, post-doctoral researchers and interns.

Mullady's five-year vibrio cell counting project is based here. He uses the same approach to screen bait, since its transfer throughout the world is also a mechanism for introducing marine life.

George Smith is packing his equipment to board an oil tanker and sample its ballast water as it travels across the ocean. Meanwhile, molecular ecologist Kathleen Coss is studying the DNA of pathogens in ballast water collected from ships crossing the Atlantic.

"We have made literally hundreds of the trips on different vessels in all the oceans, sampling and recording," Ruiz said.

In an office trailer adjacent to his main lab, Ruiz opens a door marked "Vial Library." Here the walls are lined with 10-drawer cabinets marked with scientific names of microscopic creatures.

Ruiz opens a drawer marked "Urochordates." Each plain cardboard box in the drawer contains hundreds of tiny vials, preserved samples collected in field surveys of bays and estuaries around the country. The vials represent a treasure trove of data that can be mined to understand patterns and rates of invasion throughout the nation.

"There are dozens of Ph.D. dissertations in this vial library," says Ruiz as he carefully replaces a bar-coded sample in the stacks.

Tracking system

In an adjacent office trailer is the National Ballast Water Clearinghouse, which gives the Coast Guard a way to track the "delivery patterns" of ballast water into the United States.

Ships coming from foreign ports are asked to voluntarily empty and refill their ballast tanks 200 miles from any shore in waters at least 2,000 meters deep. Exchanging the ballast water picked up in a coastal port for deep ocean water is thought to reduce the risk of invasions.

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