The transformation of long chain polyunsaturated fatty acids in benthic food webs: The role of sea urchins

► Grazer mediated transfer of macroalgal fatty acids was modelled in a laboratory. ► Faecal pellets were depleted in long chain polyunsaturated fatty acids (LC-PUFAs). ► The gonads and larvae were enriched in LC-PUFAs relative to the diet. ► The exact nature of transfer is dependent on the species of the grazer. ► Who consumes macroalgae may have implications for nearshore biogeochemistry.