ABSTRACT
Studying biological responses across several levels of organization through long periods of time may be the most useful approach to ultimately understanding how metals affect aquatic benthos. Criteria for protecting aquatic environments from trace metal contamination are necessary because of the potential toxicity of these pollutants. Attributing a biological change in a natural system to the specific influences of metals requires: demonstrating which processes are sensitive to metals; separating metal-induced changes in a process from background fluctuations; and unambiguously relating the detected change to metal exposure rather than abiotic or biotic confounding variables. Implicit in most strategies for studying metal effects is the assumption that metals are the only factor controlling biological response in an affected environment. Time scales, spatial scales beyond the local community, and nature’s inherent variability are also important in determining the ultimate community that occupies a contaminated locality.
