MEASURES OF MARINE ENVIRONMENTAL-QUALITY

In the past, measures of marine environmental quality have focused on effects of specific stressors on ecosystem components-biochemical, genetic, physiological, pathological, behavioural and community. To measure ecosystem changes resulting from multiple stresses, such as a combination of pollutants (some local and some not) and physical habitat changes including those that might arise from global warming, it is necessary to measure attributes of whole ecosystems. These include primary productivity, nutrient cycling, species diversity, instability, disease prevalence, size spectrum and contaminant effects across trophic levels. Monitoring programmes should test hypotheses regarding changes in and effects on (a) processes, such as bioaccumulation, biomass production, respiration, reproduction and eutrophication that, if impaired, may lead to changes in ecosystem structure; and (b) the structure and key system attributes of marine ecosystems.