ABSTRACT

When a person has a medical checkup, assessments of his or her health are focused mainly on the successful functioning of various systems. In contrast, assessments of ecosystem health have focused primarily on structural attributes rather than on functional attributes. Assessments of functional responses to stress seem an obvious approach to assuring the continuation of the services provided by ecosystems. This chapter addresses functional attributes in assessing the ecological consequences of contamination. It provides an introductory discussion of functional vs. structural assessment of ecosystem condition. The chapter presents some illustrative examples of assessments based on functional attributes; and some illustrative examples of statistical methods appropriate to evaluate rate processes. Sediments are the site of great biological activity in aquatic systems. The most commonly measured functional endpoints in aquatic ecosystems are production (P), respiration (R), and their ratio (P/R).