Major Research Needs

Future research must focus on the nature and extent of biological responses to chemical contaminants. If management of living resources is to be based on a realistic understanding of Chesapeake Bay ecology, we must detail the effects that representative contaminants (and especially combinations of contaminants and other stresses) have on the health and behavior of individuals, populations, and communities - in short, from the organism to the ecosystem level.

In particular, much greater emphasis must be placed on the following:

• Quantifying system-wide effects of low-level concentrations of contaminants on living organisms in the Bay. Researchers studying toxic chemicals in the Chesapeake have documented not only individual effects - such as lesions on fish - but also shifts in populations of benthic and planktonic communities due to contaminant concentrations at or very near ambient levels. Effects from more subtle concentrations are less well understood, though research on some organisms has shown effects, such as the suppression of immune response in oysters, noted above, at near-ambient levels.
  
  
• Building on research, including work done outside the Chesapeake Bay, that has shown direct effects from chronic, low-level toxicants, such as chemical preservatives on wooden bulkheads.
  
  
• Predicting where effects are likely to occur, given our understanding of the distribution of chemical contaminants and their behavior in the estuary. Of particular significance may be contaminant "gradients," whether spreading from a Region of Concern, or down a tributary or down the Bay. Predictions of distribution can prove difficult, especially in light of counter-intuitive data, such as unexpected spikes of sediment contamination in some otherwise unpolluted Eastern Shore tributaries.
  
  
• Determining the biological impacts of chemical contaminants in order to assess the real meaning of a "toxics-free Bay." Improved understanding of when metals or compounds - many of which are naturally occurring - become "toxic" will help clarify the balance between costly pollution removal and prevention on the one hand, and the economic benefits of commercially, recreationally and ecologically important Bay resources on the other.

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