Morgan 9408951 The inability of investigators to track microscopic larvae of marine animals has impeded our understanding of planktonic processes that regulate larval supply to adult populations. This project will be to adapt techniques that have been used by entomologists to study dispersal by crustacean larvae. The study will determine the feasibility of tagging barnacle and crab larvae with rare earth elements (REE) by examining uptake and persistence of marker, levels of marker passed from females to larvae and variability of rare earth elements in larvae from natural populations. The success of adapting this technique for marine animals largely depends on whether or not REEs can be accumulated and retained by animals in seawater long enough to be useful as tracers of larval movements. ***