Inhibitory effects of copper toward marine microorganisms were studied. Phosphate was found to prevent copper inhibition. Growth and phosphate flux kinetics were described. These phosphate limited systems were found to be copper sensitive only under conditions of manganese deficiency. Toxicity occurred in this normally rather resistant yeast and in hydrocarbon oxidizing microorganisms at about .000001 M. Arsenate was among a number of metabolic inhibitors found to inhibit phosphate transport; phosphate also competitively reduced arsenate uptake. Both arsenate and phosphate are accumulated by the same active transport system in which velocities increase as the hydrogen ion is increased, saturation of the system does not occur, and the transport temperature coefficient is very large. Both arsenate and copper are important at existing concentrations in the environment. When nutrients are dilute these antimetabolites prevent microbial metabolism thus affecting the steady state chemistry which they control. Toxicity levels of antimetabolites depend not only on populations and chelate concentrations but in a major way on free nutrients and trace metal levels. (Author)

"Final report to the Environmental Protection Agency, contract no. 18050 DLW." Includes bibliographical references. Microfiche.