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Ballast water carried around the world and dumped by ships is spreading harmful bacteria into the Chesapeake Bay, according to an article in an upcoming issue of the journal Nature written in part by an Old Dominion University faculty member and his research associate.

Fred Dobbs, associate professor of oceanography, and Lisa Drake, a post-doctoral research associate, along with colleagues at the University of Maryland and the Smithsonian Environmental Research Center, collaborated on the article, which will be published Nov. 2.

"Nature" is a weekly international journal of science.

Since the 19th century, ships have used ballast water stored in their hulls for stability, discharging water both in port and at sea. The United States receives more than 79 million tons of ballast water from overseas each year. The water can carry a diverse community of organisms, including those harmful to humans, plants and animals.

The researchers measured concentrations of bacteria, viral particles and the bacteria that causes human-epidemic cholera, in the ballast water of vessels arriving in the Chesapeake Bay from foreign ports. Given the vast amount of ballast water deposited in the bay, the group's data indicate that the foreign water contains large numbers of harmful, as well as non harmful, organisms.

The types of bacteria that cause human cholera were found in plankton samples from all ships surveyed and in water samples from 93 percent of the ships.

The microorganism is common in fresh water and marine habitats, Dobbs said, but new cholera bacteria from foreign ballast water can establish itself in places where it already exists.

Despite growing concern about biological invasions and emergent diseases, the extent and effects of the transfer of microorganisms in ballast water have been virtually unexplored, according to the article.

This article was posted on: October 27, 2000

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