AVAILABILITY OF COPPER FROM PHYTOPLANKTON AND WATER FOR THE BIVALVE MACOMA-BALTHICA .1. SEPARATION OF UPTAKE PATHWAYS USING THE RADIOTRACERCU-64

To study the role of food in Cu accumulation by bivalves, algae spiked with Cu can be used. With spiked algae, however, redistribution of Cu between the dissolved and the particulate phase hampers the assessmen t of the contribution of food. This occurred in efforts to label algae with the radiotracer Cu-64. A method was designed to overcome this pr oblem of redistribution. By adding excess EDTA to seawater, the biolog ical availability of dissolved Cu was minimized. The effectiveness of complexation by EDTA was controlled through adsorption on Macoma balth ica shells and uptake in M. balthica tissue.