These results suggest that in addition to metal exclusion, two other mechanisms are responsible for successful adaptation to heavy metals in Great Lakes algae. Heavy metals, especially Pb, Cd, and Zn can be incorporated in polyphosphate bodies. Metals incorporated in this manner can be transferred by direct consumption through the food chain as the authors have demonstrated in the tubificid worm. Mobilization of polyphosphate in phosphorus poor waters could internally mobilize the metal in the same organism, eventually leading to death of the organism or release of the metal to the soluble phase in an area distant from the source of the metal. Heavy metals, though not present in detectable levels in the cells may be immobilized within the cell in vacuoles. In certain organisms, these might be excreted back into the environment or produce cellular changes which may prevent certain organisms from growing and competing successfully in areas where the metals persist, leading to the growth of undesirable species.