 How can scientists trace a barely visible plastic particle across the ocean through a fish's body and onto our plates? Microplastics in the seas now outnumber the stars in our galaxy, but we still don't know exactly where these tiny pieces of rubbish end up, or what effect they're having on fish or the humans who eat them. Nuclear techniques are a very useful tool in the research of microplastic particles in the ocean because we can follow microplastic particles through the food chain. Radio tracers enable scientists to investigate whether the particles are crossing cell membranes, for example, from a mother shark through the egg case to a baby shark, or through a fish's food, such as these shrimp, into its digestive system and possibly into its brain or other organs. And they can see where the plastic pollution affects the way a fish absorbs nutrients or contaminants. This research is still new, but offers hope that we can better understand the effect of microplastics on marine life because we can't solve a problem we don't understand.