Something strange is going on in a shallow, marshy area of Virginias Elizabeth River, and the Office of Naval Research is onto it. Here is a site so polluted that when the riverbed is disturbed, oil generally bubbles up and forms a slick on the waters surface.

Yet, in this foul soup there is a thriving population of the minnow-like killifish Fundulus heteroclitus, locally known as the mummichog. Normal killifish taken from clean sites nearby cant survive exposure in the laboratory to these conditions, but the resident mummichog tolerates this environment, we believe, through adaptation to the chronic pollution. As a matter of fact, these fish go belly-up when introduced to nice, clean water.

For 300 years the Elizabeth River flowing into the Chesapeake Bay has been a highly industrialized area the site of civilian and military shipbuilding, shoreside commerce, and associated manufacturing and processing. At this particular site, river sediments are highly contaminated by creosote, pentachlorophenol, and other chemicals used by a wood treatment plant that operated nearby for most of the previous century. (Creosote contains some of the same cancer-causing chemicals found in cigarette smoke.) The cleanup of this site is ongoing (its been designated a Superfund site), but scientists want to know how the local mummichog has been able to adapt to such nasty contamination.

How do they do it? wonders Dr. Linda Chrisey, ONRs program manager on the study, These fish have apparently become acclimated to the contaminants, perhaps through altered expression of certain genes, and their progeny apparently inherit the ability to tolerate these conditions, too. Theres some very interesting science going on here. Chrisey is supporting Richard Di Giulio at Duke University to determine which pollutants are eliciting which responses in the fish.

Although the selective pressures on these fish is so great that their genomes are changed, and these change
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Contact: Gail S. Cleere
cleereg@onr.navy.mil
703-696-4987
Office of Naval Research
5-Apr-2002