ABSTRACT
Measurement of the sublethal effects of toxic chemicals on aquatic organisms involves tests in which morphologic or behavioral responses are measured in vivo. In vivo nuclear magnetic resonance (NMR) spectroscopy can meet these requirements, because it can focus on biochemical and physiological processes in intact, non- stressed organisms. Organisms lacking obvious respiratory movements, again including echinoderms and mollusks, are preferred, as the rhythmic beating of fish opercula may reduce NMR signal clarity. Surface probe localized NMR allows uncontaminated signal acquisition from discrete muscles. Surface probe localized NMR can measure sublethal biochemical actions in intact aquatic organisms maintained in simulated environmental conditions. The use of surface probe localized 31P NMR allows a number of sublethal metabolic actions to be monitored. NMR reveals only "free" metabolites; changes in peak intensities can also arise from changes in metabolite mobilization, as with adenosine diphosphate and inorganic phosphate during ischemic hypoxia.
